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<article article-type="research-article" dtd-version="1.1" specific-use="sps-1.9" xml:lang="en" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">
	<front>
		<journal-meta>
			<journal-id journal-id-type="publisher-id">cjas</journal-id>
			<journal-title-group>
				<journal-title>Cuban Journal of Agricultural Science</journal-title>
				<abbrev-journal-title abbrev-type="publisher">Cuban J. Agric. Sci.</abbrev-journal-title>
			</journal-title-group>
			<issn pub-type="epub">2079-3480</issn>
			<publisher>
				<publisher-name>Ediciones ICA</publisher-name>
			</publisher>
		</journal-meta>
		<article-meta>
			<article-id pub-id-type="publisher-id">00006</article-id>
			<article-categories>
				<subj-group subj-group-type="heading">
					<subject>Animal Science</subject>
				</subj-group>
			</article-categories>
			<title-group>
				<article-title>Performance traits of growing pigs fed on diets of royal palm nut meal</article-title>
			</title-group>
			<contrib-group>
				<contrib contrib-type="author">
					<name>
						<surname>Oliva</surname>
						<given-names>D.</given-names>
					</name>
					<xref ref-type="aff" rid="aff1"><sup>1</sup></xref>
					<xref ref-type="corresp" rid="c1">*</xref>
				</contrib>
				<contrib contrib-type="author">
					<name>
						<surname>Martínez</surname>
						<given-names>Mayuly</given-names>
					</name>
					<xref ref-type="aff" rid="aff1"><sup>1</sup></xref>
				</contrib>
				<contrib contrib-type="author">
					<name>
						<surname>Jiménez</surname>
						<given-names>Leydis</given-names>
					</name>
					<xref ref-type="aff" rid="aff1"><sup>1</sup></xref>
				</contrib>
				<contrib contrib-type="author">
					<name>
						<surname>Ly</surname>
						<given-names>J.</given-names>
					</name>
					<xref ref-type="aff" rid="aff1"><sup>1</sup></xref>
				</contrib>
				<aff id="aff1">
					<label>1</label>
					<institution content-type="original">Instituto de Ciencia Animal, Apartado No. 24, San José de las Lajas, Cuba</institution>
					<institution content-type="normalized">Instituto de Ciencia Animal</institution>
					<institution content-type="orgname">Instituto de Ciencia Animal</institution>
					<addr-line>
						<city>San José de las Lajas</city>
					</addr-line>
					<country country="CU">Cuba</country>
				</aff>
			</contrib-group>
			<author-notes>
				<corresp id="c1">
					<label>*</label>Email: <email>doliva@ica.co.cu</email>
				</corresp>
			</author-notes>
			<pub-date date-type="pub" publication-format="electronic">
				<day>01</day>
				<month>06</month>
				<year>2018</year>
			</pub-date>
			<pub-date date-type="collection" publication-format="electronic">
				<season>Apr-Jun</season>
				<year>2018</year>
			</pub-date>
			<volume>52</volume>
			<issue>2</issue>
			<fpage>173</fpage>
			<lpage>180</lpage>
			<history>
				<date date-type="received">
					<day>20</day>
					<month>07</month>
					<year>2017</year>
				</date>
				<date date-type="accepted">
					<day>04</day>
					<month>05</month>
					<year>2018</year>
				</date>
			</history>
			<permissions>
				<license license-type="open-access" xlink:href="https://creativecommons.org/licenses/by-nc/4.0/" xml:lang="en">
					<license-p>This is an open-access article distributed under the terms of the Creative Commons Attribution License</license-p>
				</license>
			</permissions>
			<abstract>
				<title>Abstract</title>
				<p>This study evaluated the feeding of fattening pigs with variable levels of royal palm nuts, fruit of the Cuban royal palm (<italic>Roystonea regia</italic> H.B.K. Cook). The royal palm nuts was ground together with the rest of the ingredients of the diet, after being dried in the open air. The royal palm nut meal contained 39.18 and 6.62 % of crude fiber and crude protein (Nx6.25), respectively. Performance traits were evaluated in 24 commercial crossbred pigs (Yorkshire x Landrace x Duroc), females and castrated males equal in proportion, with an initial average weight of 26 kg, randomly distributed in four treatments consisting of diets with 0, 10, 20 and 30 % of royal palm nut meal, on dry basis. A completely randomized design with 2x4 factorial arrangement was used. The factors were sex and the level of royal palm nut meal in the food. The test lasted 65 days. There was no effect (P&gt;0.05) on the sex x royal palm nut level interaction in any of the measurements. Neither effect (P&gt;0.05) was found in the final weight nor in the daily gain (706, 630, 660 and 680 g/day). It is highly recommended to feed growing pigs with diets containing up to 30% of royal palm nut meal. It is suggested to carry out performance tests in which pigs reach a slaughter weight equal or superior to 100 kg and studies in breeding sows.</p>
			</abstract>
			<kwd-group xml:lang="en">
				<title>Key words:</title>
				<kwd>pigs</kwd>
				<kwd>royal palm</kwd>
				<kwd>intake</kwd>
				<kwd>gain</kwd>
				<kwd>food conversion</kwd>
			</kwd-group>
			<funding-group>
				<award-group award-type="contract">
					<funding-source>Use of palm products in the production of pigs and rabbits</funding-source>
					<award-id>PY P131-LH002.24</award-id>
				</award-group>
			</funding-group>
			<counts>
				<fig-count count="0"/>
				<table-count count="12"/>
				<equation-count count="0"/>
				<ref-count count="36"/>
				<page-count count="8"/>
			</counts>
		</article-meta>
	</front>
	<body>
		<p>Royal palm nut is the fruit of the Cuban royal palm tree (<italic>Roystonea regia</italic> H.B.K. Cook). Royal palm tree is one of the most numerous trees in Cuba, with an approximate existence between 12 and 15 million. With a mean production of 40-60 kg/palm/year, an average production of around 600 thousand tons of palm nuts per year is calculated (<xref ref-type="bibr" rid="B33">Valdivié and Bicudo, 2011</xref>).</p>
		<p>Palm nuts are one of the main energy alternative feed available in Cuba due to their high content of fat or oil, which has the double of digestible energy of fiber (<xref ref-type="bibr" rid="B4">Arias <italic>et al.</italic> 2016</xref>). Therefore, although fiber fraction of palm nuts showed a low digestive use due to its polymeric nature with β-glycosidic links (<xref ref-type="bibr" rid="B6">Bach Knudsen 2011</xref>), this is compensated by lipid digestibility, which is practically complete (<xref ref-type="bibr" rid="B5">Ayala and Ly 2017</xref> and <xref ref-type="bibr" rid="B20">Ly <italic>et al.</italic> 2017</xref>).</p>
		<p>At the Institute of Animal Science, <xref ref-type="bibr" rid="B11">Díaz <italic>et al.</italic> (1989</xref>) recommended the inclusion of royal palm nuts in the diets of growing pigs in a proportion of up to 40 %, for fattening animals at a level of 60 % and for pregnant sows at a level of 30 % in unconventional low energy density diets, mainly manufactured with food waste (half-cooked food) and sugar cane molasses. In studies conducted by <xref ref-type="bibr" rid="B1">Abeledo <italic>et al.</italic> (2004</xref>) and <xref ref-type="bibr" rid="B12">Díaz <italic>et al.</italic> (2010)</xref>, royal palm nuts have been used in swine feeding, although certain factors such as genotype or particle size could have a negative influence on the data obtained in these circumstances (<xref ref-type="bibr" rid="B21">Ly <italic>et al.</italic> 2015</xref>).</p>
		<p>The objective of this experiment was to determine performance traits in growing pigs fed diets partially replaced by royal palm nut meal.</p>
		<sec sec-type="materials|methods">
			<title>Materials and Methods</title>
			<p><italic>Experimental design and animals</italic>. A completely randomized design with 2x4 factorial arrangement was used to study performance traits in 24 commercial crossbred pigs (Yorkshire x Landrace x Duroc), females and castrated males in the same proportion and with an initial mean weight of 26 kg. The animals belonged to the herd of the Institute of Animal Science. These pigs were randomly distributed in four treatments consisting of diets with 0, 10, 20 and 30 % of royal palm nut meal, on a dry basis (<xref ref-type="table" rid="t1">Table 1</xref>). The factors were sex and the level of royal palm nut meal in the food.</p>
			<p>
				<table-wrap id="t1">
					<label>Table 1</label>
					<caption>
						<title>Chemical composition of royal palm nut</title>
					</caption>
					<graphic xlink:href="2079-3480-cjas-52-02-173-gt1.jpg"/>
					<table-wrap-foot>
						<fn id="TFN1">
							<label><sup>1</sup></label>
							<p><italic>In natura</italic></p>
						</fn>
						<fn id="TFN2">
							<label><sup>2</sup></label>
							<p>Calculate according to <xref ref-type="bibr" rid="B24">Nehring and Haenlein (1973</xref>)</p>
						</fn>
					</table-wrap-foot>
				</table-wrap>
			</p>
			<p>
				<table-wrap id="t2">
					<label>Table 2</label>
					<caption>
						<title>Composition of experimental diets (percentage under dry basis)</title>
					</caption>
					<graphic xlink:href="2079-3480-cjas-52-02-173-gt2.jpg"/>
					<table-wrap-foot>
						<fn id="TFN3">
							<label><sup>1</sup></label>
							<p>Vitamins and trace elements according to <xref ref-type="bibr" rid="B26">NRC (2012)</xref>
							</p>
						</fn>
					</table-wrap-foot>
				</table-wrap>
			</p>
			<p><italic>Preparation of the royal palm nut oil</italic>. The royal palm nut, with around 30 % of <italic>in natura</italic> DM was obtained in the El Uvero farm, belonging to the enterprise Flora y Fauna, in Jaruco municipality, Mayabeque province. Drying process of royal palm nut consisted of manually removing the palm nuts. Later, they were exposed to the sun by spreading the seeds in a drying plate, for 5 consecutive days, from 8:00 am to 4:30 p.m., picking up the material in bags before nightfall to avoid the increase of humidity due to the night dew.</p>
			<p>Dry material was stored in bags, under roof, in buildings with adequate ventilation and low humidity level. It was ground together with the rest of the components of the diet of grains and cereals in the corresponding proportion every 5 days. This way, it was allowed to extend the useful life of the royal palm nut meal because it is known (<xref ref-type="bibr" rid="B22">Ly <italic>et al.</italic> 2005</xref>, <xref ref-type="bibr" rid="B29">Santana, 2006</xref>, <xref ref-type="bibr" rid="B12">Díaz <italic>et al.</italic> 2010</xref>, <xref ref-type="bibr" rid="B34">Valdivié and Castro (2010</xref>) and <xref ref-type="bibr" rid="B10">Caro <italic>et al.</italic> 2014</xref>) that royal palm nut rapidly becomes rancid, decreasing its biological quality and palatability by animals. In addition, grinding the nuts, rich in fat, was facilitated without clogging the mill. A representative sample of the lot was taken, to know its physical and chemical characteristics. <xref ref-type="table" rid="t1">Table 1</xref> shows the characteristics of the chemical composition of the palm nuts that were used in the test.</p>
			<p><italic>Diet preparation</italic>. Diets were produced with grains and formulated to contain variable levels (0, 10, 20 and 30 % on dry basis) of royal palm nut meal. <xref ref-type="table" rid="t2">Table 2</xref> shows the characteristics of diets.</p>
			<p>
				<xref ref-type="table" rid="t3">Table 3</xref> shows the nutrient content of experimental diets. As expected, as more royal palm nut meal was included in the feed, fiber percentage and fat in the diet increased, and crude protein content decreased. As a result, the energy: protein ratio was also modified. No fits were made to establish isoproteic or isoenergetic diets.</p>
			<p>
				<table-wrap id="t3">
					<label>Table 3</label>
					<caption>
						<title>Nutrient content of experimental diets (percentage under dry basis)</title>
					</caption>
					<graphic xlink:href="2079-3480-cjas-52-02-173-gt3.jpg"/>
				</table-wrap>
			</p>
			<p><italic>Animals and management</italic>. All individuals included in the test were apparently healthy, without clinical symptoms of any disease, and conveniently dewormed. Animals were housed in individual pens with cement floors and steel frames, in an open stable. Each of these pens was provided with a feeding trough and drinking trough.</p>
			<p>Pigs were randomly distributed in the four treatments, with six repetitions each and a 2x4 factorial arrangement, consisting of four diets supplied according to the recommended daily intake scale in Cuba in conventional feeding intensive systems during growth, according to the Porcine Breeding Manual of the Instituto de Investigaciones Porcinas (<xref ref-type="bibr" rid="B14">IIP 2008</xref>). <xref ref-type="table" rid="t4">Table 4</xref> shows the feeding scale used. Drinking water was always available. Animals were weighed at the beginning of the experiment and every fifteen days in order to know the evolution of body weight gain curve. The experiment concluded when animals reached around 70 kg of weight, about 65 days after having begun, as an approximate average.</p>
			<p><italic>Chemical analysis</italic>. Most of the nutrients, except NDF, that were measured according to <xref ref-type="bibr" rid="B32">Van Soest <italic>et al.</italic> (1991</xref>), were determined by duplicate in representative samples, regarding known procedures (<xref ref-type="bibr" rid="B2">AOAC 2005</xref>). As it is established (<xref ref-type="bibr" rid="B4">Arias <italic>et al.</italic> 2016</xref>), concentration of organic matter was obtained from subtracting ash percentage from 100, nitrogen-free extract (NFE) was the consequence of subtracting concentrations of ash, crude fiber, ether extract and crude protein (Nx6.25) from 100, while the heat content was estimated from the chemical composition of royal palm nut through the use of <xref ref-type="bibr" rid="B24">Nehring and Haenlein (1973</xref>) equation, as in the other cases (<xref ref-type="bibr" rid="B4">Arias <italic>et al.</italic> 2016</xref>; <xref ref-type="bibr" rid="B20">Ly <italic>et al.</italic> 2017</xref>). All chemical determinations were carried out by duplicate.</p>
			<p>
				<table-wrap id="t4">
					<label>Tabla 4</label>
					<caption>
						<title>Feeding scale for growing pigs (humid basis)</title>
					</caption>
					<graphic xlink:href="2079-3480-cjas-52-02-173-gt4.png"/>
					<table-wrap-foot>
						<fn id="TFN4">
							<p>Source: <xref ref-type="bibr" rid="B14">IIP (2008)</xref>
							</p>
						</fn>
					</table-wrap-foot>
				</table-wrap>
			</p>
			<p><italic>Statistical analysis</italic>. Data were processed according to a completely randomized design with 2x4 factorial arrangement, in which factors were sex and diet (<xref ref-type="bibr" rid="B30">Steel <italic>et al.</italic> 1997</xref>), and the statistical package InfoStat (<xref ref-type="bibr" rid="B7">Balzarini <italic>et al.</italic> 2001</xref>) was used for their manage-ment.</p>
		</sec>
		<sec sec-type="results">
			<title>Results</title>
			<p>During the test, no animal showed any symptom of discomfort that could indicate any disorder apart from the performance test.</p>
			<p>No differences were found (P&gt;0.05) in the interaction sex x diet in any measure. <xref ref-type="table" rid="t5">Table 5</xref> shows data of performance test regarding sex.</p>
			<p>Final weight of castrated males showed no differences (P&gt;0.10). In addition, there was no effect of sex on daily mean gain nor on food conversion, of DM and protein.</p>
			<p>
				<xref ref-type="table" rid="t6">Table 6</xref> shows the effect of including variable levels of royal palm nut meal in the diets. There was no significant effect (P&gt;0.05) on final weight nor on daily gain with the increase of royal palm nut in the food. In the case of protein conversion, there was no statistical difference among treatments but, from a biological point of view, there was a tendency (P&lt;0.078) to be lower with the increase of royal palm nut meal in the diet for pigs.</p>
			<p>
				<table-wrap id="t5">
					<label>Table 5</label>
					<caption>
						<title>Performance traits of pigs fed royal palm nut meal. Effect of sex</title>
					</caption>
					<graphic xlink:href="2079-3480-cjas-52-02-173-gt5.jpg"/>
					<table-wrap-foot>
						<fn id="TFN5">
							<label><sup>1</sup></label>
							<p>Intake at scale. For details, see full text</p>
						</fn>
					</table-wrap-foot>
				</table-wrap>
			</p>
			<p>
				<table-wrap id="t6">
					<label>Table 6</label>
					<caption>
						<title>Performance traits of pigs fed royal palm nut meal. Effect of inclusion level</title>
					</caption>
					<graphic xlink:href="2079-3480-cjas-52-02-173-gt6.jpg"/>
					<table-wrap-foot>
						<fn id="TFN6">
							<label><sup>1</sup></label>
							<p>Intake at scale. For some details, see full text</p>
						</fn>
					</table-wrap-foot>
				</table-wrap>
			</p>
		</sec>
		<sec sec-type="discussion">
			<title>Discussion</title>
			<p>Data related to nutrient content of royal palm nuts used in this research showed similar characteristics to those of the representative samples from the western part of the country or from other places in Cuba (<xref ref-type="bibr" rid="B22">Ly <italic>et al.</italic> 2005</xref>, <xref ref-type="bibr" rid="B9">Caro <italic>et al.</italic> 2015</xref> and <xref ref-type="bibr" rid="B4">Arias <italic>et al.</italic> 2016</xref>). Therefore, it was considered that the experimental results were representative of royal palm nuts existing in Cuba, or at least from the western part.</p>
			<p>Except data of <xref ref-type="bibr" rid="B8">Batista (2015</xref>), who studied feeding of castrated male and female pigs in groups with royal palm nut meal, there were no antecedents of this research belonging to the effect of sex on pigs fed royal palm nuts (<xref ref-type="bibr" rid="B21">Ly <italic>et al.</italic> 2015</xref>). Results found in the present study with animals individually housed, are in accordance with the generally accepted fact that castrated male pigs show better performance traits that females (<xref ref-type="bibr" rid="B31">Tribble 1991</xref>). About this matter, <xref ref-type="bibr" rid="B8">Batista (2015)</xref> also found better performance traits in castrated males regarding females. This information may be valuable for the design of feeding systems of developing female pigs for being used as reproducers fed with royal palm nut meal, from which there are no references either (<xref ref-type="bibr" rid="B35">Wahlstrom 1991</xref>).</p>
			<p>The inclusion of royal palm nut meal for replacing from 0 up to 30 % of the diet was due to the well-known fact that pig fattening by agreement, the pig state enterprise provides 70 % of food needs and pig farmers supply the remaining 30 % (<xref ref-type="bibr" rid="B8">Batista 2015</xref> and <xref ref-type="bibr" rid="B3">Arias 2016</xref>). In the substitution range designed in the present experiment, it could be logical to expect that an increase of royal palm nut meal in the food should have negative consequences in the performance traits due to the growing inclusion of fiber fraction in the food (<xref ref-type="bibr" rid="B36">Wenk 2001</xref>, <xref ref-type="bibr" rid="B6">Bach Knudsen 2011</xref>, <xref ref-type="bibr" rid="B16">Kerr and Shurson 2013</xref>, <xref ref-type="bibr" rid="B18">Lindberg 2014</xref> and <xref ref-type="bibr" rid="B15">Jha and Berrocoso 2015</xref>). Such thing did not happen and there could be many causes for these results. First of all, royal palm nut meal was obtained here when grinding this food resource with the rest of ingredients of the diet formula, which assured a very efficient grinding of food, with an evident reduction of particle size. It is well known that a decrease of particle size contributes to a better digestive use of food (<xref ref-type="bibr" rid="B17">Kim <italic>et al.</italic> 2005</xref> and <xref ref-type="bibr" rid="B19">Ly 2008</xref>). Consequently, it determines better performance traits (<xref ref-type="bibr" rid="B23">Mavromichalis <italic>et al.</italic> 2000</xref>; <xref ref-type="bibr" rid="B25">Ngoc <italic>et al.</italic> 2011</xref>). On the other hand, rectal digestibility indexes found with the same diets in another parallel experiment (<xref ref-type="bibr" rid="B27">Oliva <italic>et al.</italic> 2017</xref>), are in agreement with this hypothesis.</p>
			<p>It should also be considered the important contribution of lipid substances within royal palm nuts to the diet, and that they have demonstrated a high digestive use (<xref ref-type="bibr" rid="B5">Ayala and Ly 2017</xref>). This way, even though fiber fraction of royal palm nuts determines a decrease of the energy density of diet, ether extract, mainly constituted by medium chain fatty acids or long chain unsaturated acids, usually shows a very efficient digestive use (<xref ref-type="bibr" rid="B19">Ly 2008</xref>), and, without doubts, this tends to counteract this negative effect of fiber fraction. The high contribution of fats to increase energy density of food is well-known (<xref ref-type="bibr" rid="B24">Nehring and Haenlein 1973</xref>).</p>
			<p>Another cause could be that guaranteeing a constant and homogeneous feeding, such as the one carried out in this research, could contribute the good results. In previous experiments, together with the supply of royal palm nuts without grinding to the animals, mixing it with sugar cane molasses, could contribute to worsening performance traits of economic interest, like those reported in other researches (<xref ref-type="bibr" rid="B13">García <italic>et al.</italic> 2001</xref> and <xref ref-type="bibr" rid="B1">Abeledo <italic>et al.</italic> 2004</xref>).</p>
			<p>Finally, the use a feeding at scale like the one suggested under Cuban conditions of commercial fattening (<xref ref-type="bibr" rid="B14">IIP 2008</xref>) could contribute to an improvement of performance traits because it is also very well-known that, under <italic>ad libitum</italic> feeding conditions, food conversion has a remarkable deterioration (<xref ref-type="bibr" rid="B31">Tribble 1991</xref> and <xref ref-type="bibr" rid="B28">Patience <italic>et al.</italic> 2015</xref>). This subject requires more research.</p>
			<p>It is advisable to feed growing pigs with diets that contain up to 30 % of royal palm nut meal. It is suggested to conduct performance traits in other categories, like reproducer sows.</p>
		</sec>
	</body>
	<back>
		<ack>
			<title>Acknowledgements</title>
			<p>This research was financed by the Project “Use of palm products in the production of pigs and rabbits” (PY P131-LH002.24). This evaluation would not be posible without the collaboration of workers of ¨El Uvero¨ farm, belonging to the enterprise Flora y Fauna, Mayabeque, who provided the royal palm nuts without cost. Thanks also to workers from plant of concentrated feed of the Institute of Animal Science due to their special care for grinding the royal palm nuts used in this experiment. In addition, thanks to technicians, mainly Ms. Olga Martínez, from the Instituto de Investigaciones Porcinas, Punta Brava, where chemical analysis of food for this experiment were carried out.</p>
		</ack>
		<ref-list>
			<title>References</title>
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					<source>Revista Computadorizada de Producción Porcina</source>
					<volume>11</volume>
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					<publisher-name>Association of Official Agricultural Chemists (AOAC)</publisher-name>
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							<surname>Horwitz</surname>
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						</name>
						<name>
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	<sub-article article-type="translation" id="s1" xml:lang="es">
		<front-stub>
			<article-categories>
				<subj-group subj-group-type="heading">
					<subject>Ciencia Animal</subject>
				</subj-group>
			</article-categories>
			<title-group>
				<article-title>Rasgos de comportamiento de cerdos en crecimiento, alimentados con dietas de harina de palmiche</article-title>
			</title-group>
			<contrib-group>
				<contrib contrib-type="author">
					<name>
						<surname>Oliva</surname>
						<given-names>D.</given-names>
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					<xref ref-type="aff" rid="aff2"><sup>1</sup></xref>
					<xref ref-type="corresp" rid="c2">*</xref>
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				<contrib contrib-type="author">
					<name>
						<surname>Martínez</surname>
						<given-names>Mayuly</given-names>
					</name>
					<xref ref-type="aff" rid="aff2"><sup>1</sup></xref>
				</contrib>
				<contrib contrib-type="author">
					<name>
						<surname>Jiménez</surname>
						<given-names>Leydis</given-names>
					</name>
					<xref ref-type="aff" rid="aff2"><sup>1</sup></xref>
				</contrib>
				<contrib contrib-type="author">
					<name>
						<surname>Ly</surname>
						<given-names>J.</given-names>
					</name>
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				</contrib>
				<aff id="aff2">
					<label>1</label>
					<institution content-type="original">Instituto de Ciencia Animal, Apartado No. 24, San José de las Lajas, Cuba</institution>
					<institution content-type="normalized">Instituto de Ciencia Animal</institution>
					<institution content-type="orgname">Instituto de Ciencia Animal</institution>
					<addr-line>
						<city>San José de las Lajas</city>
					</addr-line>
					<country country="CU">Cuba</country>
				</aff>
			</contrib-group>
			<author-notes>
				<corresp id="c2">
					<label>*</label>Email: <email>doliva@ica.co.cu</email>
				</corresp>
			</author-notes>
			<abstract>
				<title>Resumen</title>
				<p>Se evaluó la alimentación de cerdos en ceba con niveles variables de palmiche, fruto de la palma real cubana (<italic>Roystonea regia</italic> H.B.K. Cook). El palmiche se molió con el resto de los ingredientes de la dieta, después de secarse al aire libre. La harina de palmiche contenía 39.18 y 6.62 % de fibra cruda y proteína bruta (N x 6.25), respectivamente. Se evaluaron rasgos de comportamiento en 24 cerdos de cruce comercial (Yorkshire x Landrace x Duroc), machos castrados y hembras en igual proporción, con peso promedio inicial de 26 kg, distribuidos aleatoriamente en cuatro tratamientos. Las dietas consistieron en 0, 10, 20 y 30% de harina de palmiche, en base seca. Se utilizó un diseño completamente aleatorizado con arreglo factorial 2 x 4. Los factores fueron el sexo y el nivel de harina de palmiche en el alimento. La prueba duró 65 días. No hubo efecto (P&gt;0.05) en la interacción sexo x nivel de palmiche en las medidas hechas. Tampoco se halló efecto (P&gt;0.05) en el peso final ni en la ganancia diaria (706, 630, 660 y 680 g/d). Es muy recomendable alimentar cerdos en crecimiento con dietas que contengan hasta 30% de harina de palmiche. Se sugiere realizar pruebas de comportamiento, en las que los cerdos alcancen un peso de sacrificio, igual o superior a 100 kg, además de estudios en cerdas reproductoras.</p>
			</abstract>
			<kwd-group xml:lang="es">
				<title>Palabras clave:</title>
				<kwd>ganado porcino</kwd>
				<kwd>palma real</kwd>
				<kwd>consumo</kwd>
				<kwd>ganancia</kwd>
				<kwd>conversión alimentaria</kwd>
			</kwd-group>
		</front-stub>
		<body>
			<p>El palmiche es el fruto de la palma real cubana (<italic>Roystonea regia</italic> H.B.K. Cook). La palma real es uno de los árboles más numerosos de Cuba, existen aproximadamente entre 12 y 15 millones. Con una producción promedio de 40-60 kg/palma/año, se calcula un aproximado de 600 mil toneladas de palmiche al año (<xref ref-type="bibr" rid="B33">Valdivié y Bicudo 2011</xref>).</p>
			<p>El palmiche es uno de los principales alimentos alternativos energéticos disponibles en Cuba, debido a su alto contenido en grasa o aceite, que tiene el doble de energía digestible de la fibra (<xref ref-type="bibr" rid="B4">Arias <italic>et al.</italic> 2016</xref>). Por eso, aunque la fracción fibrosa del palmiche presente bajo aprovechamiento digestivo por su naturaleza polimérica con β-enlaces glucosídicos (<xref ref-type="bibr" rid="B6">Bach Knudsen 2011</xref>), esto se compensa con la digestibilidad de los lípidos, que es prácticamente completa (<xref ref-type="bibr" rid="B5">Ayala y Ly 2017</xref> y <xref ref-type="bibr" rid="B20">Ly <italic>et al.</italic> 2017</xref>).</p>
			<p>En el Instituto de Ciencia Animal, <xref ref-type="bibr" rid="B11">Díaz <italic>et al.</italic> (1989</xref>) recomendaron la inclusión del palmiche en las dietas para cerdos en crecimiento en proporción de hasta 40 %, en las destinadas a animales en ceba 60 % y para las cerdas gestantes 30 %. Se trata de dietas no convencionales, de baja densidad energética, fabricadas fundamentalmente con desperdicios de alimento (sancocho) y mieles de caña. En estudios realizados por <xref ref-type="bibr" rid="B1">Abeledo <italic>et al.</italic> (2004</xref>) y <xref ref-type="bibr" rid="B12">Díaz <italic>et al.</italic> (2010)</xref> se ha utilizado el palmiche en la alimentación porcina, aunque ciertos factores, como el genotipo o el tamaño de partícula, pudieron influir negativamente en los datos obtenidos en esas circunstancias (<xref ref-type="bibr" rid="B21">Ly <italic>et al.</italic> 2015</xref>).</p>
			<p>El objetivo de este experimento fue determinar rasgos de comportamiento en cerdos en crecimiento, alimentados con dietas parcialmente sustituidas por harina de palmiche.</p>
			<sec sec-type="materials|methods">
				<title>Materiales y Métodos</title>
				<p><italic>Diseño experimental y animales</italic>. Se utilizó un diseño completamente aleatorizado, con arreglo factorial 2 x 4, para estudiar rasgos de comportamiento en 24 cerdos de cruce comercial (Yorkshire x Landrace x Duroc), machos castrados y hembras en la misma proporción, con peso promedio inicial de 26 kg. Los individuos pertenecían a la piara del Instituto de Ciencia Animal. Se distribuyeron aleatoriamente en cuatro tratamientos, que consistieron en dietas con 0, 10, 20 y 30% de harina de palmiche, en base seca (<xref ref-type="table" rid="t7">Tabla 1</xref>). Los factores fueron el sexo y el nivel de harina de palmiche en el alimento.</p>
				<p><italic>Preparación de la harina de palmiche</italic>. El palmiche, con aproximadamente 30 % de MS <italic>in natura</italic>, se obtuvo en la finca El Uvero, perteneciente a la empresa Flora y Fauna, en el municipio Jaruco, de la provincia Mayabeque. El proceso de secado consistió en desprender las semillas de palmiche de forma manual. Más tarde, se procedió a la exposición al sol mediante la extensión de las semillas en un plato de secado, durante cinco días consecutivos, desde 8:00 a.m. hasta 4:30 p.m. El material se recogió antes del anochecer para evitar el incremento de la humedad a causa del rocío nocturno.</p>
				<p>El material seco se almacenó en sacos, bajo techo, en naves con adecuada ventilación y bajo nivel de humedad. Se molió, cada cinco días, con el resto de los componentes de la dieta de granos y cereales, en la proporción correspondiente. Se alargó así la vida útil de la harina de palmiche, pues se sabe (<xref ref-type="bibr" rid="B22">Ly <italic>et al.</italic> 2005</xref>, <xref ref-type="bibr" rid="B29">Santana 2006</xref>, <xref ref-type="bibr" rid="B12">Díaz <italic>et al.</italic> 2010</xref>, <xref ref-type="bibr" rid="B34">Valdivié y Castro (2010</xref>) y <xref ref-type="bibr" rid="B10">Caro <italic>et al.</italic> 2014</xref>) que el palmiche se enrancia con rapidez, lo que disminuye su calidad biológica y palatabilidad por parte de los animales. Además, se facilitó la molienda de los granos de palmiche ricos en grasa, sin atascar el molino. Posteriormente, se tomó una muestra representativa del lote para conocer sus características físicas y químicas. En la <xref ref-type="table" rid="t7">tabla 1</xref> aparecen las características de la composición química del palmiche utilizado en la prueba.</p>
				<p><italic>Preparación de las dietas</italic>. Las dietas se confeccionaron con granos y se formularon para contener niveles variables de harina de palmiche (0, 10, 20 y 30 % en base seca). Las características de las dietas se muestran en la <xref ref-type="table" rid="t8">tabla 2</xref>.</p>
				<p>
					<table-wrap id="t7">
						<label>Table 1</label>
						<caption>
							<title>Chemical composition of royal palm nut</title>
						</caption>
						<graphic xlink:href="2079-3480-cjas-52-02-173-gt7.jpg"/>
						<table-wrap-foot>
							<fn id="TFN7">
								<label><sup>1</sup></label>
								<p><italic>In natura</italic></p>
							</fn>
							<fn id="TFN8">
								<label><sup>2</sup></label>
								<p>Calculate according to <xref ref-type="bibr" rid="B24">Nehring and Haenlein (1973</xref>)</p>
							</fn>
						</table-wrap-foot>
					</table-wrap>
				</p>
				<p>
					<table-wrap id="t8">
						<label>Table 2</label>
						<caption>
							<title>Composition of experimental diets (percentage under dry basis)</title>
						</caption>
						<graphic xlink:href="2079-3480-cjas-52-02-173-gt8.png"/>
						<table-wrap-foot>
							<fn id="TFN9">
								<label><sup>1</sup></label>
								<p>Vitamins and trace elements according to <xref ref-type="bibr" rid="B26">NRC (2012)</xref>
								</p>
							</fn>
						</table-wrap-foot>
					</table-wrap>
				</p>
				<p>En la <xref ref-type="table" rid="t9">tabla 3</xref> se presenta el contenido de nutrientes de las dietas experimentales. Como era de esperar, en la medida que se incluyó más harina de palmiche en el alimento, aumentó el porcentaje de fibra y grasa en la dieta, y decreció el contenido de proteína bruta. Como resultado, también se modificó la relación energía:proteína. No se hicieron ajustes para establecer dietas isoproteicas o isoenergéticas.</p>
				<p>
					<table-wrap id="t9">
						<label>Table 3</label>
						<caption>
							<title>Nutrient content of experimental diets (percentage under dry basis)</title>
						</caption>
						<graphic xlink:href="2079-3480-cjas-52-02-173-gt9.jpg"/>
					</table-wrap>
				</p>
				<p><italic>Animales y manejo</italic>. Todos los animales incluidos en la prueba estaban aparentemente sanos, sin síntomas clínicos de padecimiento de alguna enfermedad, y convenientemente desparasitados. Se alojaron en corrales individuales, con piso de cemento y armazón de acero, en un establo abierto. Cada uno de estos corrales estaba provisto de un comedero y bebedero.</p>
				<p>Los cerdos se distribuyeron al azar en los cuatro tratamientos, con seis repeticiones cada uno, con arreglo factorial 2 x 4. Las dietas establecidas fueron cuatro, suministradas de acuerdo con la escala de consumo diario recomendada en Cuba en sistemas intensivos de alimentación convencional durante el crecimiento, según el Manual de Crianza Porcina del Instituto de Investigaciones Porcinas (<xref ref-type="bibr" rid="B14">IIP 2008</xref>). En la <xref ref-type="table" rid="t10">tabla 4</xref> se presenta la escala de alimentación utilizada. El agua de bebida siempre estuvo disponible. Los animales se pesaron al inicio del experimento y cada quince días para conocer la evolución de la curva de aumento de peso corporal. El experimento concluyó cuando alcanzaron un peso de aproximadamente 70 kg, cerca de 65 d después de haber comenzado.</p>
				<p><italic>Análisis químico</italic>. La mayoría de los nutrientes, con excepción de la FDN, que se midieron de acuerdo con <xref ref-type="bibr" rid="B32">van Soest <italic>et al.</italic> (1991)</xref> se determinaron por duplicado en muestras representativas, según los procedimientos reconocidos (<xref ref-type="bibr" rid="B2">AOAC 2005</xref>). Como está establecido (<xref ref-type="bibr" rid="B4">Arias <italic>et al.</italic> 2016</xref>), la concentración de materia orgánica resultó de restar de 100 el porcentaje de cenizas. El extracto libre de nitrógeno (ELN) fue la consecuencia de restar de cien la suma de las concentraciones de ceniza, fibra cruda, extracto etéreo y proteína bruta (Nx6.25). El contenido calorífico se estimó a partir de la composición química del palmiche, mediante el uso de la ecuación de <xref ref-type="bibr" rid="B24">Nehring y Haenlein (1973</xref>), como se ha hecho en otros estudios (<xref ref-type="bibr" rid="B4">Arias <italic>et al.</italic> 2016</xref>, <xref ref-type="bibr" rid="B20">Ly <italic>et al.</italic> 2017</xref>). Todas las determinaciones químicas se hicieron por duplicado.</p>
				<p>
					<table-wrap id="t10">
						<label>Tabla 4</label>
						<caption>
							<title>Feeding scale for growing pigs (humid basis)</title>
						</caption>
						<graphic xlink:href="2079-3480-cjas-52-02-173-gt10.jpg"/>
						<table-wrap-foot>
							<fn id="TFN11">
								<p>Source: <xref ref-type="bibr" rid="B14">IIP (2008)</xref>
								</p>
							</fn>
						</table-wrap-foot>
					</table-wrap>
				</p>
				<p><italic>Análisis estadístico</italic>. Los datos se procesaron de acuerdo con un diseño completamente aleatorizado, con arreglo factorial 2x4. Los factores fueron el sexo y la dieta (<xref ref-type="bibr" rid="B30">Steel <italic>et al.</italic> 1997</xref>) y la manipulación se realizó mediante el uso del paquete estadístico de InfoStat (<xref ref-type="bibr" rid="B7">Balzarini <italic>et al.</italic> 2001</xref>).</p>
			</sec>
			<sec sec-type="results">
				<title>Resultados</title>
				<p>Durante el transcurso de la prueba ningún animal mostró síntoma de malestar, que pudiera indicar algún trastorno de naturaleza ajena a la prueba de comportamiento.</p>
				<p>No se encontraron diferencias (P&gt;0.05) en la interacción sexo x dieta en ninguna medida. Los datos de la prueba de comportamiento, en cuanto al efecto de sexo se muestran en la <xref ref-type="table" rid="t11">tabla 5</xref>.</p>
				<p>El peso final de los machos castrados no presentó diferencias (P&gt;0.10). Tampoco hubo efecto del sexo en la ganancia media diaria ni en la conversión alimentaria, de MS como de proteína.</p>
				<p>El efecto de incluir niveles variables de harina de palmiche en la dieta se muestra en la <xref ref-type="table" rid="t12">tabla 6</xref>. No hubo efecto significativo (P&gt;0.05) en el peso final ni en la ganancia diaria con el aumento del contenido de harina de palmiche en la dieta, aunque la conversión alimentaria de MS aumentó ligeramente con el incremento de palmiche en el alimento. En el caso de la conversión de proteína, no hubo diferencia estadística entre los tratamientos, pero desde el punto de vista biológico la tendencia fue a ser menor (P&lt;0.078) con el aumento de la harina de palmiche en la dieta de los cerdos.</p>
				<p>
					<table-wrap id="t11">
						<label>Table 5</label>
						<caption>
							<title>Performance traits of pigs fed royal palm nut meal. Effect of sex</title>
						</caption>
						<graphic xlink:href="2079-3480-cjas-52-02-173-gt11.png"/>
						<table-wrap-foot>
							<fn id="TFN10">
								<label><sup>1</sup></label>
								<p>Intake at scale. For details, see full text</p>
							</fn>
						</table-wrap-foot>
					</table-wrap>
				</p>
				<p>
					<table-wrap id="t12">
						<label>Table 6</label>
						<caption>
							<title>Performance traits of pigs fed royal palm nut meal. Effect of inclusion level</title>
						</caption>
						<graphic xlink:href="2079-3480-cjas-52-02-173-gt12.jpg"/>
						<table-wrap-foot>
							<fn id="TFN12">
								<label><sup>1</sup></label>
								<p>Intake at scale. For some details, see full text</p>
							</fn>
						</table-wrap-foot>
					</table-wrap>
				</p>
			</sec>
			<sec sec-type="discussion">
				<title>Discusión</title>
				<p>Los datos relativos al contenido de nutrientes del palmiche mostraron características similares a las de las muestras representativas del occidente de Cuba o de otros lugares del país (<xref ref-type="bibr" rid="B22">Ly <italic>et al.</italic> 2005</xref>, <xref ref-type="bibr" rid="B9">Caro <italic>et al.</italic> 2015</xref> y <xref ref-type="bibr" rid="B4">Arias <italic>et al.</italic> 2016</xref>). Por consiguiente, se consideró que los resultados experimentales fueron característicos de un palmiche representativo del que existe en Cuba o, al menos, en su parte oeste.</p>
				<p>Con excepción de los datos de <xref ref-type="bibr" rid="B8">Batista (2015</xref>), quien estudió la alimentación de cerdos machos castrados y hembras, alimentados en grupo con harina de palmiche, no existían antecedentes de esta investigación, en cuanto al efecto de sexo en los cerdos alimentados con palmiche (<xref ref-type="bibr" rid="B21">Ly <italic>et al.</italic> 2015</xref>). Los resultados que aquí se informan, con animales alojados individualmente, están en concordancia con lo generalmente aceptado. Esto es, los cerdos machos castrados exhiben mejores rasgos de comportamiento que las hembras (<xref ref-type="bibr" rid="B31">Tribble 1991</xref>). Sobre este particular, <xref ref-type="bibr" rid="B8">Batista (2015)</xref> también refirió mejores rasgos de comportamiento en cerdos machos castrados con respecto a hembras. Esta información pudiera ser valiosa para el diseño de sistemas de alimentación de cerdas en desarrollo, con vistas a ser reproductoras alimentadas con harina de palmiche, de lo que tampoco hay referencias (<xref ref-type="bibr" rid="B35">Wahlstrom 1991</xref>).</p>
				<p>La inclusión de harina de palmiche en sustitución, desde 0 hasta 30% de la dieta, obedeció a que en la ceba de cerdos por convenio, la empresa estatal porcina acuerda suministrar 70 % de las necesidades de alimento para el engorde de los animales, mientras que el porcicultor debe suplir 30 % (<xref ref-type="bibr" rid="B8">Batista 2015</xref> y <xref ref-type="bibr" rid="B3">Arias 2016</xref>). En el rango de sustitución que se diseñó en este experimento, en principio, se pudiera esperar que el incremento de la harina de palmiche en el alimento debiera tener consecuencias adversas en los rasgos de comportamiento, debido a la incorporación creciente de la fracción fibrosa en la comida (<xref ref-type="bibr" rid="B36">Wenk 2001</xref>, <xref ref-type="bibr" rid="B6">Bach Knudsen 2011</xref>, <xref ref-type="bibr" rid="B16">Kerr y Shurson 2013</xref>, <xref ref-type="bibr" rid="B18">Lindberg 2014</xref> y <xref ref-type="bibr" rid="B15">Jha y Berrocoso 2015</xref>). Esto no sucedió, y varias pudieran ser las causas. En primer lugar, la harina de palmiche se obtuvo al moler este recurso alimentario con el resto de los ingredientes de la fórmula dietética, lo que aseguró una molida muy eficiente, con reducción evidente del tamaño de partícula. Es conocido que la disminución del tamaño de partícula contribuye a un mejor aprovechamiento digestivo del alimento (<xref ref-type="bibr" rid="B17">Kim <italic>et al.</italic> 2005</xref> y <xref ref-type="bibr" rid="B19">Ly 2008</xref>) y, en consecuencia, determina mejores rasgos de comportamiento (<xref ref-type="bibr" rid="B23">Mavromichalis <italic>et al.</italic> 2000</xref>; <xref ref-type="bibr" rid="B25">Ngoc <italic>et al.</italic> 2011</xref>). Por otra parte, los índices de digestibilidad rectal, hallados con estas mismas dietas en otro experimento hecho en paralelo (<xref ref-type="bibr" rid="B27">Oliva <italic>et al.</italic> 2017</xref>), están en concordancia con esta hipótesis.</p>
				<p>También se pudiera considerar el aporte importante a la dieta de sustancias lipídicas presentes en el palmiche, que han mostrado alto aprovechamiento digestivo (<xref ref-type="bibr" rid="B5">Ayala y Ly 2017</xref>). De esta manera, si bien la fracción fibrosa del palmiche determina una disminución en la densidad energética de la dieta, el extracto etéreo, constituido fundamentalmente por ácidos grasos de cadena media, o insaturados de cadena larga, suele mostrar un aprovechamiento digestivo muy eficiente (<xref ref-type="bibr" rid="B19">Ly 2008</xref>). Indudablemente, ello tiende a contrarrestar ese efecto negativo de la fracción fibrosa. Se sabe además, la alta contribución de las grasas a elevar la densidad energética del alimento (<xref ref-type="bibr" rid="B24">Nehring y Haenlein 1973</xref>).</p>
				<p>En tercer lugar, el garantizar una alimentación constante y homogénea, como la que se refiere en esta investigación, pudo contribuir a los buenos resultados. En experimentos anteriores, unido al suministro de palmiche a los animales, sin que estuviese molido, el hecho de mezclarlo con melaza de caña de azúcar pudo contribuir a empeorar los rasgos de comportamiento que son de interés económico, como los informados por <xref ref-type="bibr" rid="B13">García <italic>et al.</italic> (2001</xref>) y <xref ref-type="bibr" rid="B1">Abeledo <italic>et al.</italic> (2004</xref>).</p>
				<p>Por último, el seguir una alimentación a escala, como la sugerida en condiciones cubanas de ceba comercial (<xref ref-type="bibr" rid="B14">IIP 2008</xref>), pudo contribuir a mejorar los rasgos de comportamiento, ya que en condiciones de alimentación <italic>ad libitum</italic>, la conversión alimentaria experimenta un deterioro notable (<xref ref-type="bibr" rid="B31">Tribble 1991</xref> y <xref ref-type="bibr" rid="B28">Patience <italic>et al.</italic> 2015</xref>). Este tema requiere de investigaciones futuras.</p>
				<p>Es recomendable alimentar cerdos en crecimiento con dietas que contengan hasta 30 % de harina de palmiche. Se sugiere realizar pruebas de comportamiento en otras categorías, como son las cerdas reproductoras.</p>
			</sec>
		</body>
		<back>
			<ack>
				<title>Agradecimientos</title>
				<p>Se agradece al proyecto “Uso de productos de palma en la producción de ganado porcino y cunícula” (PY P131-LH002.24) por el financiamiento para esta investigación. Esta evaluación no hubiera sido posible sin la cooperación de los trabajadores de la granja ¨El Uvero¨, perteneciente a la Empresa de Flora y Fauna, en Mayabeque, quienes suministraron el palmiche sin costo alguno. Los autores desean expresar su gratitud a los trabajadores de la planta elaboradora de alimentos concentrados del Instituto de Ciencia Animal, por su especial cuidado en la molida del palmiche utilizado en este experimento. También se agradece a los técnicos, particularmente a la Sra. Olga Martínez, del Instituto de Investigaciones Porcinas, en Punta Brava, donde se llevó a cabo el análisis químico de los alimentos utilizados en la investigación.</p>
			</ack>
		</back>
	</sub-article>
</article>