ABSTRACT: This study evaluated chromium and quantitative and qualitative feed restriction as alternative nutritional strategies to ractopamine in finishing barrows. Fifty barrows, genetically similar, with an initial body weight of 99.0 ± 4.3 kg and a final body weight of 117.2 ± 5.8 kg were used. The animals were distributed in a randomized complete block design with five nutritional treatments (Control; Rac = 10ppm ractopamine; Chromium = 0,8mg chromium yeast; Quality = qualitative restriction, 7.5% less net energy in the diet; Quanti = 15% quantitative reduction in feed supply), with five replicates and two animals per replicate. Chromium supplementation and quantitative feed restriction reduced feed, lysine, net energy, and crude protein intakes (P < 0.05). Chromium, ractopamine, and quantitative restriction improved feed conversion (P < 0.05). Supplementation with chromium and ractopamine and feed restriction did not influence the carcass characteristics of the pigs (P < 0.05). Quantitative feed restriction and supplementation of 0.8mg of chromium yeast are presented as potential alternatives to ractopamine in the diet of finishing pigs.

RESUMO: O estudo foi conduzido com o objetivo de avaliar o cromo e restrições alimentares quantitativa e qualitativa como estratégias nutricionais alternativas a ractopamina para suínos machos castrados em terminação. Foram utilizados 50 suínos machos castrados, geneticamente similares, com peso inicial de 99,0 ± 4,3 kg e final de 117,2 ± 5,8 kg. Os animais foram distribuídos em delineamento experimental de blocos ao acaso em cinco tratamentos nutricionais (Controle; Rac = 10ppm de ractopamina; Cromo = 0,8mg de cromo levedura; Qualit = restrição qualitativa com menos 7,5% de energia líquida na dieta e Quanti = redução quantitativa de 15% no fornecimento de ração), com cinco repetições e dois animais por repetição. A suplementação de cromo e a restrição alimentar quantitativa reduziram (P < 0,05) os consumos de ração, lisina digestível, energia líquida e proteína bruta. O cromo, a ractopamina e a restrição quantitativa melhoraram (P < 0,05) a conversão alimentar. A suplementação de cromo, ractopamina e as restrições alimentares não influenciam (P < 0,05) as características de carcaça dos suínos. A restrição alimentar quantitativa e a suplementação de 0,8 mg de cromo levedura se apresentam como potenciais alternativas para a substituição da ractopamina nas dietas.

RESUMO: Este estudo foi conduzido com o objetivo de identificar os efeitos da suplementação com ractopamina, cromo picolinato, cromo levedura, ou da restrição alimentar energética, sobre o desempenho e o perfil de ácidos graxos da gordura subcutânea de fêmeas suínas em fase final de terminação. Foram utilizadas 20 fêmeas suínas, geneticamente similares, com peso inicial de 105,35 ± 4,77 kg e peso final de 131,37 ± 5,58 kg, distribuídas em delineamento experimental de blocos ao acaso em cinco tratamentos (controle; ractopamina: 20 ppm; picolinato de cromo: 0,48 ppm; cromo levedura: 0,80 ppm; e restrição energética: -150 kcal kg-1 de energia metabolizável) com quatro repetições de um animal cada. As dietas experimentais foram isonutritivas, exceto para o nível de energia metabolizável da dieta fornecida ao grupo submetido à restrição energética. Não houve efeito dos tratamentos sobre o desempenho e as características de carcaça. As suplementações com ractopamina e cromo orgânico (picolinato ou levedura) aumentaram a concentração de ácidos graxos poli-insaturados. A proporção do ácido α-linolênico foi maior com a inclusão da ractopamina ou do cromo levedura na dieta. A restrição energética aumentou a proporção n-6:n-3 e reduziu a concentração do ácido α-linolênico. As suplementações com ractopamina, picolinato de cromo, cromo levedura, ou restrição alimentar energética, não influenciaram o desempenho e as características de carcaça, mas alteraram o perfil lipídico da gordura subcutânea de fêmeas suínas. As suplementações com ractopamina e cromo orgânico aumentaram a proporção de AGPI.

ABSTRACT: This study identified the effects of dietary supplementation with ractopamine, chromium picolinate, chromium yeast, or an energetic feed restriction on the growth performance and lipid profile of subcutaneous fat, in late finishing gilts. Twenty genetically similar gilts with initial body weight of 105.35 ± 4.77 kg and a final body weight of 131.37 ± 5.58 kg were distributed in a completely randomized block design with five treatments (control; ractopamine: 20 ppm; chromium picolinate: 0.48 ppm; chromium yeast: 0.80 ppm; and energetic feed restriction: -150 kcal kg-1 of metabolizable energy), with four replicates of one animal each. The experimental diets were isonutritives, except for the metabolizable energy level of the diet fed to the group subjected to energy restriction. There were no effects on the growth performance and carcass characteristics. Ractopamine and organic chromium (picolinate and yeast) supplementation increased the concentration of total polyunsaturated fatty acid. The proportion of α-linolenic fatty acids were higher when the diets were supplemented with ractopamine or chromium yeast. The energy restriction increased the n-6:n-3 ratio and reduced α-linolenic acid concentration. Therefore, ractopamine, chromium picolinate, chromium yeast supplementation, and energetic feed restriction did not affect the growth performance or carcass characteristics but altered the lipid profile of subcutaneous fat in finishing gilts. Ractopamine and organic chromium supplementation increased PUFA in the fat of finishing female pigs.

RESUMO: Realizou-se este estudo com o objetivo de avaliar as suplementações de cromo e a restrição energética em substituição a ractopamina para leitoas em terminação tardia. Foram utilizadas 60 leitoas, com pesos inicial de 98,87±0,25 kg e final de 122,69 ± 10,97 kg, distribuídas em delineamento de blocos ao acaso com cinco dietas: controle; cromo levedura (0,8 ppm); picolinato de cromo (0,48 ppm); ractopamina (20 ppm) e restrição energética (redução de 150 kcal de EMkg-1 de ração), com seis repetições e dois animais por unidade experimental. A dieta contendo ractopamina proporcionou melhor (P<0,05) conversão alimentar e maior peso de carcaça quente das leitoas. A dieta contendo ractopamina apresentou menor (P<0,05) custo de ração por quilograma de ganho e maior índice de eficiência econômica em relação as dietas contendo cromo e restrição energética que, por sua vez, foram superiores em comparação a dieta controle. Dietas suplementadas com cromo e ractopamina apresentaram maior (P<0,05) percentual e quantidade de carne magra e maior índice de bonificação de carcaça em relação a dieta controle e restrição energética. Concluiu-se que a redução energética não prejudica as respostas das leitoas em relação a dieta controle. A suplementação de ractopamina possibilita melhor conversão alimentar, menor custo de ração por quilograma de ganho e maior índice de eficiência econômica. As suplementações de cromo e ractopamina expressam aumento do percentual e quantidade de carne magra e do índice de bonificação das carcaças. O picolinato de cromo e o cromo levedura são potenciais substitutos a ractopamina para otimizar as características de carcaça das leitoas.

ABSTRACT: This study evaluated chromium supplements and energy restriction as substitutes for ractopamine in the diets of late finishing gilts. Sixty gilts were used, with initial weights of 98.87 ± 0.25 kg and final weights of 122.69 ± 10.97 kg, distributed in a randomized block design with five diets: control; yeast chromium (0.8 ppm); chromium picolinate (0.48 ppm); ractopamine (20 ppm) and energy restriction (reduction of 150 kcal of EM kg-1 of feed), with six replicates and two animals per experimental unit. Feeding diet containing ractopamine enabled better (P<0.05) feed conversion and greater weights of the hot carcass of the gilts. The diet containing ractopamine exhibited a lower (P<0.05) cost of feed per kilogram of gain and higher economic efficiency, when compared to diets containing chromium and energy restriction; these exhibited better outcomes, compared to the control diet. Diets supplemented with chromium and ractopamine resulted in a higher (P<0.05) percentage and quantity of lean meat and a higher rate of carcass bonus, when compared to the control diet and energy restriction. The energy reduction did not harm the gilts’ responses, compared to the control diet. Ractopamine supplementation allowed for a better feed conversion, lower feed cost per kilogram of gain, and a higher economic efficiency index. Supplements of chromium and ractopamine increased the percentage and quantity of lean meat and the bonus index of the carcasses. Therefore, chromium picolinate and chromium yeast are potential substitutes for ractopamine for optimizing the gilts carcass characteristics.

RESUMO: Realizou-se este estudo com o objetivo de avaliar os efeitos de níveis de cromo levedura e lisina digestível, desempenho e características de carcaça de suínos em terminação. Foram utilizados 64 machos castrados com peso inicial de 72,77 ± 7,20 kg e final de 119,44 ± 9,47 kg, distribuídos em esquema fatorial 2 x 2, sendo dois níveis (Cr0: 0 ppb e Cr800: 800 ppb) e dois níveis de lisina digestível (L0: nível recomendado e L+10%: 10%). A temperatura do ar registrada de 30,9 ± 3,7 ºC durante o período experimental foi considerada como de estresse por calor. As variáveis de desempenho não foram influenciadas (P>0,05), contudo L+10% aumentou (P<0,05) o consumo de lisina digestível diário. As características de carcaça dos animais não foram influenciadas (P>0,05) pelos níveis de cromo levedura e lisina digestível. A suplementação de 800 ppb de cromo levedura, e o aumento em 10% do nível de lisina digestível, isolados ou associados, não melhoram o desempenho e as características de carcaça de suínos em terminação submetidos a temperaturas ambientais elevadas.

ABSTRACT: This study evaluated the effects of chromium yeast and digestible lysine levels on the performance and carcass characteristics of finishing pigs. Sixty-four barrows with an initial weight of 72.77 ± 7.20 kg and final weight of 119.44 ± 9.47 kg were used, distributed in a 2 x 2 factorial scheme, with two levels of chromium yeast (Cr0: 0 ppb and Cr800: 800 ppb) and two levels of digestible lysine (L0: recommended level and L+10%: 10%). The recorded air temperature of 30.9 ± 3.7 ºC during the experimental period was considered as heat stress. Performance variables were not influenced (P>0.05); however, L+10% showed an increase (P<0.05) in daily digestible lysine intake. Carcass characteristics of the animals were not influenced (P>0.05) by the chromium or digestible lysine levels. Supplementation with 800 ppb of yeast chromium and a 10% increase in the level of digestible lysine, isolated or associated, did not improve the performance and carcass characteristics of finishing pigs, subjected to high ambient temperatures.

ABSTRACT The objective of the present study was to evaluate the effects of cooling systems by negative pressure versus directed ducts on the performance of lactating sows and their litter. The experiment was conducted in a tropical climatic region in Brazil. Ninety-four lactating sows during 26.2±1.7 days of lactation were included with their 1,236 piglets. Sows were distributed using a completely randomized block design into two treatments: a negative pressure cooling (NPC) system and a directed duct cooling (DDC) system. We adopted sow parity as blocking criterion. During the experimental period, environmental temperatures inside the farrowing rooms were 22.9±1.5 and 25.4±2.5 °C, respectively, using the NPC and DDC systems. Sow daily feed intake, litter weight at weaning, piglet weight at weaning, litter daily weight gain, piglet daily gain, and daily milk production per sow were greater in the NPC system than in the DDC system. The type of cooling system did not affect piglet weight after standardization, mortality, number of piglets weaned per sow, and estrus return. The use of an NPC system can reduce the effects of higher environmental temperatures better than the DDC system. The NPC system allowed for greater feed intake, piglet and litter weight gain, weight of piglets and litter at weaning, and milk production compared with the DDC system.

ABSTRACT This study was conducted to evaluate different nutritional plans of net energy (NE) with a constant calorie:nutrient ratio on the performance of piglets from 7 to 30 kg. Sixty barrows with an initial weight of 7.11±0.89 kg were distributed among five nutritional plans: two NE-decreasing plans (A and B, starting from NE concentrations of 2.47 and 2.52 Mcal kg−1, respectively, and ending both at 2.37 Mcal kg−1) and three NE-constant plans (C, 2.37 Mcal kg−1; D, 2.42 Mcal kg−1; and E, 2.47 Mcal kg−1). The nutritional plans were composed of two decreasing plans: A, 2.47-2.42-2.37-2.37-2.37 Mcal of NE kg−1 of feed; B, 2.52-2.47-2.42-2.37-2.37 Mcal of NE kg−1 of feed; and three constant plans: C, 2.37 Mcal of NE kg−1 of feed; D, 2.42 Mcal of NE kg−1 of feed; E, 2.47 Mcal of NE kg−1 of feed, from 7 to 10, 10 to 15, 15 to 20, 20 to 25, and 25 to 30 kg, respectively, with six replicates per treatment and two animals per experimental unit. Animal performance was evaluated through the following measurements: average daily feed intake (ADFI), NE intake, standardized ileal digestible lysine intake (SID Lys intake), average daily gain (ADG), feed:gain ratio (F:G), final weight (FW), feed cost per kg of weight gain (CWG), economic efficiency index (EEI), and fecal score. Piglets’ final weight was 32.95±3.30 kg. Considering the total experimental period, there was no effect of the nutritional plan on ADG, F:G, CWG, and EEI. The final weight of piglets under plan D was higher than that recorded for those allocated to plan C, not differing from the other nutritional plans. Piglets fed under nutritional plans A and D presented higher ADFI compared with those subjected to other plans. Net energy and SID Lys intakes were significantly higher in piglets subjected to plans A, D, and E compared with those under plans B and C. Net energy nutritional plans did not influence the fecal score and the occurrence of diarrhea of the piglets. Based on our analysis, a nutritional plan containing a constant NE level of 2.42 Mcal kg−1 of feed may be recommended for piglets from 7 to 30 kg.

RESUMO: Realizou-se este estudo com o objetivo de avaliar planos sequenciais de energia metabolizável (EM), mantendo a relação lisina: caloria, para leitões dos 7 ao 30 kg. Foram utilizados 48 leitões, fêmeas, com peso inicial de 6,9 ± 1,2 kg e final de 30,5 ± 3,8 kg, distribuídos em delineamento de blocos ao acaso em três planos nutricionais, sendo: 1- 3.300-3.250-3.200-3.150 Kcal de EM kg-1 de ração; 2- 3.400-3.350-3.300-3.250 Kcal de EM kg-1 de ração; e 3- 3.500-3.450-3.400-3.350 Kcal de EM kg-1 de ração, dos 7 aos 10 kg, dos 10 aos 15 kg, dos 15 aos 20 kg e dos 20 aos 30 kg, respectivamente, com oito repetições e dois animais por unidade experimental. Dos 7 aos 10 kg, não houve efeito (P>0,05) dos planos nutricionais nas variáveis avaliadas. Observou-se, dos 7 aos 15 kg, maiores (P<0,05) consumos de energia e ganho de peso e melhor (P < 0,05) conversão alimentar nos animais alimentados com os planos nutricionais 2 e 3. Os leitões alimentados com os planos nutricionais 2 e 3 apresentaram maior (P<0,05) peso final, consumos de ração, de energia, de lisina digestível, ganho de peso e melhor conversão alimentar nos períodos dos 7 aos 20 kg, dos 7 aos 25 kg e dos 7 aos 30 kg. Recomenda-se o plano sequencial contendo 3.400-3.350-3.300-3.250 Kcal de EM kg-1 de ração dos 7 aos 10 kg, dos 10 aos 15 kg, 15 aos 20 kg e dos 20 aos 30 kg, respectivamente, equivalentes aos níveis de 2.546-2.513-2.501-2.475 Kcal de energia líquida kg-1 de ração.

ABSTRACT: The objective of this study was to evaluate sequential metabolizable energy (ME) plans, maintaining the lysine: calorie ratio for piglets from 7 to 30 kg. Forty eight female piglets with initial weight of 6.9 ± 1.2 kg and final weight of 30.5 ± 3.8 kg were randomly allocated in a randomized complete blocks design to three nutritional plans with eight replicates and two animals per experimental unit. Sequential plans provided four ME levels: plan 1: 3,300-3,250-3,200-3,150 kcal ME kg-1, plan 2: 3,400-3,350-3,300-3,250 kcal ME kg-1, and plan 3: 3,500-3,450-3,400-3,350 kcal ME kg-1 of feed, from 7 to 10 kg, 10 to 15 kg, 15 to 20 kg and 20 to 30 kg, respectively. From 7 to 10 kg, there was no effect (P>0.05) of the nutritional plans in the evaluated variables. From 7 to 15 kg, a higher (P<0.05) energy intake and weight gain and a better (P < 0.05) feed conversion was observed in animals fed with nutritional plans 2 and 3. Nutritional plans 2 and 3 resulted in higher (P<0.05) final weight, feed intake, energy intake, digestible lysine intake, weight gain, and better feed conversion in the 7 to 20 kg, 7 to 25 kg and 7 to 30 kg. It is recommended the sequential plan containing 3,400-3,350-3,300-3,250 kcal ME kg-1 of feed from 7 to 10 kg, from 10 to 15 kg, 15 to 20 kg, and from 20 to 30 kg; respectively, equivalent to levels of 2,546-2,513-2,501-2,475 kcal net energy (NE) kg-1 of feed for piglets.