ABSTRACT This study aimed to evaluate the effects of zinc oxide and a low level of encapsulated zinc oxide, with or without dietary fiber, on the performance and intestinal health of weaned piglets. A total of 112 piglets were used, divided into four treatment groups: basal diet with zinc oxide (ZnO); basal diet with zinc oxide and dietary fiber (ZnO+DF); basal diet with encapsulated low zinc oxide (LZnOE); and basal diet with LZnOE and DF (LZnOE+DF). Piglets were challenged with E . coli K88 + , weighed weekly and the fecal score was evaluated daily. One pig per pen was slaughtered to evaluate the production of volatile fatty acids, intestinal microbial populations, intestinal morphology, and digestibility. The encapsulated zinc resulted in lower body weight and average daily gain, but, when associated with dietary fiber, had similar results to zinc oxide. Until 49 days of age, zinc oxide reduced diarrhoea ( p < 0.05). At 63 days of age the piglets subjected to LZnOE+DF treatment had lower diarrhoea than the pigs subjected to LZnOE treatment but higher than the ZnO and the ZnO+DF groups. Final weight and incidence of diarrhoea of pigs receiving LZnOE was worse than ZnO. LZnOE associated with DF provided the same final weight of piglets from the ZnO group.

RESUMO O objetivo com o trabalho foi avaliar a viabilidade econômica da suplementação de L-arginina em dietas para matrizes suínas durante a fase de lactação. Um estudo de caso descritivo foi realizado para identificar a viabilidade econômica da suplementação de L-arginina na ração de lactação, em relação à dieta controle, sobre o desempenho produtivo de matrizes suínas hiperprolíficas e suas leitegadas. O estudo foi realizado em uma granja comercial localizada no estado de Minas Gerais. Analisou critérios de viabilidade como o produto físico marginal (MPPg) e margem bruta (GM) no cenário de eficiência técnica e econômica, que foram comparados com o GM no grupo controle. A eficiência técnica foi estabelecida em 0,71% de L-arginina no consumo diário de ração de acordo com trabalho de campo prévio realizado pelos autores, enquanto a eficiência econômica obtida neste estudo foi de 0,43% de suplementação. A relação entre o preço da L-arginina e o preço de venda dos leitões determinou diretamente a viabilidade econômica, comparado ao grupo controle. Assim, considerando inicialmente o preço de um leitão como R$ 9,76/kg, o custo da L-arginina não deve exceder 6,61 vezes esse valor; isto é, estima-se em até R$ 64,50. Portanto, ao preço final de L-arginina de R$ 54,88, um leitão deve ser vendido ao preço de R$ 8,30/kg para tornar a suplementação de L-arginina na dieta de matrizes suínas em fase de lactação economicamente viáveis.

ABSTRACT The objective of this study was to evaluate the economic viability of L-arginine supplementation in diets for sows during the lactation phase. A descriptive case study was carried out to identify the economic viability of the supplementation of L-arginine in the lactation ration, in relation to the control diet, on the productive performance of hyper prolific sows and their litters. The study was carried out on a commercial farm located in the state of Minas Gerais. It analyzed feasibility criteria such as the marginal physical product (MPPg) and gross margin (GM) in the scenario of technical and economic efficiency, which were compared to the GM in the control group. Technical efficiency was established at 0.71% of L-arginine in daily feed intake according to previous fieldwork by the authors, while economic efficiency obtained in this study was 0.43% supplementation. The relationship between the L-arginine price and the sale price of the piglets directly determined the economic viability, compared to the control group. Thus, initially considering the price of a piglet as R$ 9.76/kg, the cost of L-arginine should not exceed 6.61 times this value; that is, it is estimated at up to R$ 64.50. Therefore, at the final price of L-arginine of R$ 54.88, a piglet should be sold at a price of R$ 8.30/kg to make the supplementation of L-arginine in the diet of lactation-phase swine economically possible.

ABSTRACT The objective of this study was to evaluate the effect of L-arginine supplementation in lactation diets on the productive and reproductive performance of pluriparous sows and their litters. Seventy-six sows of the same genetic line were assigned to four treatments in a completely randomized design with 19 replicates. The experimental unit was the sow and its respective litter. Treatments comprised a control diet (no L-arginine supplementation) and other three diets obtained by top dressing the control diet with 0.5, 1.0, and 1.5% of L-arginine. L-arginine supplementation had no effect on any performance variables, body condition, milk production, or weaning-estrus interval. There was a quadratic effect on percentage of protein and fat in milk as well as on the daily production of these components. Protein and fat percentage declined during lactation. Adding L-arginine to the diet had a quadratic effect on piglet weight at 13 and 21 days, the optimal level of L-arginine supplementation being estimated as 0.64% and 0.71%, respectively. L-arginine supplementation had a quadratic effect on the weight gain of piglets during the first 13 days and on total period of lactation, the optimal level of L-arginine supplementation being estimated as 0.60% and 0.70%, respectively. Supplementing lactation diets with 0.70% of L-arginine, corresponding to 45 g day−1, improves the weight gain of piglets by improving the nutritional quality of sow milk.

RESUMO Objetivou-se com esse trabalho avaliar o uso de programas de luz sobre o desempenho, concentração plasmática de melatonina e comportamento de suínos em fase de terminação. O experimento foi conduzido no setor de suinocultura da UFLA, utilizando-se 32 suínos em fase de terminação, por 48 dias. Os animais foram alojados em grupos de dois em cada baia (unidade experimental), distribuídos em delineamento em blocos casualizados, de acordo com o peso inicial com quatro tratamentos e quatro blocos. Foram utilizados quatro programas de luz (tratamentos), sendo T1: luz natural (LN); T2: 15 horas de luz e nove de escuro por dia (15L: 9E); T3: 19 horas de luz por dia (19L: 5E); T4: 23 horas de luz por dia (23L: 1E). As variáveis analisadas foram o desempenho (consumo de ração médio diário, ganho de peso médio diário e conversão alimentar), concentração plasmática de melatonina e o comportamento (bebendo, fuçando, ócio e comendo). A alteração no fotoperíodo não alterou o desempenho ou a concentração plasmática de melatonina nos suínos. As variáveis comportamentais “fuçando”, “comendo”, “bebendo”, não diferiram em nenhum dos períodos estudados, porém o comportamento ócio foi mais ocorrente nos suínos que receberam 15 horas de luz. O aumento no fotoperíodo não permitiu expressivas alterações de desempenho ou de comportamento dos animais.

SUMMARY The aim of this study was to evaluate the use of lighting programs on performance, plasma concentration of melatonin and behavior of finishing pigs. The experiment was conducted in the pig farming sector UFLA, using 32 pigs in the finishing phase, for 48 days. The animals were housed in groups of two in each pen (experimental unit), distributed in a randomized block design, according to the initial weight. Four light periods were used (treatments): T1: natural light (LN); T2: 15 hours of light and dark by day nine (15L: 9E); T3: 19 hours light per day (19L: 5E); T4: 23 hours of light per day (23L: 1D). The variables analyzed were the performance (average daily feed consumption, average daily gain weight and feed conversion), the plasma concentrations of melatonin and the behavior (drinking, sniffing, leisure and eating). The change in photoperiod did not affect performance or melatonin concentration in pigs. The behavioral variables "digging", "eating", "drinking", did not differ in any of the periods studied, but leisure behavior was more occurring to the pigs receiving 15 hours of light. The increase in photoperiod showed no significant changes in performance or behavior of the animals.

Avaliaram-se diferentes níveis de inclusão da raspa integral da raiz de mandioca (RIM) com o objetivo de avaliar o desempenho produtivo e a metabolizabilidade da matéria seca, da proteína bruta e da energia bruta de frangos de corte, no período de um a 21 dias de idade. No ensaio de desempenho, foram utilizadas 400 aves fêmeas da linhagem Ross e para o de metabolismo, 100 frangos machos da mesma linhagem. O delineamento experimental dos dois ensaios foi o de blocos ao acaso, com cinco tratamentos, quatro repetições e 20 aves alojadas em cada boxe para o ensaio de desempenho. Cinco aves foram alojadas em cada gaiola metabólica, para o estudo de metabolismo. Os tratamentos consistiram de rações contendo 0, 5, 10, 15 e 20% de inclusão de RIM. A RIM mandioca pode ser incluída em até 5,1% na ração de frangos de corte, no período de 1 a 21 dias, sem comprometimento da conversão alimentar e do índice de eficiência produtiva. As variáveis de metabolizabilidade da matéria seca, da proteína bruta, da energia bruta e o balanço de nitrogênio das rações não são influenciadas pelos níveis de inclusão da RIM em até 20%, no período de um a 21 dias.

The study was conducted to evaluate the effect of including whole cassava root scrapings (WCS) in diets of broilers on performance and the metabolizability of dry matter, crude protein, and gross energy and on nitrogenous balance. Four hundred female and 100 male broilers from Ross strain were used in the performance and metabolism studies, respectively. In both studies, broilers were allotted in completely randomized block design with five treatments and four replicates. The experimental unit was represented for twenty birds per box for performance study and five birds per metabolic cage for metabolism study. The treatments consisted of diets containing 0, 5, 10, 15, and 20% WCS inclusion. Up to 5.1% WCS can be included in the diet of broilers from 1 to 21 without compromising feed conversion and productive efficiency index. Dry matter, crude protein, and gross energy metabolizability and the nitrogen balance of the diets are not influenced by the inclusion of whole cassava root scrapings up to 20% in diets of broilers from 1 to 21 days of age.

Foram utilizados 50 suínos machos castrados, com alto potencial genético para deposição de carne magra na carcaça e peso inicial de 60,5 ± 1,58 kg para avaliar diferentes níveis de lisina digestível sobre o desempenho e as características de carcaça. Foi usado o delineamento de blocos ao acaso, com cinco tratamentos, cinco repetições e dois animais por repetição. Os tratamentos consistiram de cinco níveis de lisina digestível (0,600; 0,700; 0,800; 0,900 e 1,000% de lisina) obtidos variando-se a proporção de milho e farelo de soja nas rações. Os animais permaneceram no experimento até atingirem o peso final de 95,8 ± 2,64 kg. Os níveis de lisina influenciaram de forma quadrática a conversão alimentar e a conversão alimentar em músculo, que melhoraram até o nível de 0,85% de lisina digestível, e o rendimento de carne magra, que aumentou até o nível de 0,840% de lisina digestível. O consumo de lisina diário aumentou de forma linear em razão dos níveis de lisina da ração. Não houve efeito dos tratamentos sobre o ganho de peso, consumo de ração, características de carcaça, rendimento de carcaça, rendimento de gordura e rendimento de pernil. Conclui-se que suínos machos castrados, dos 60 aos 95 kg, exigem 0,850% de lisina digestível, correspondente a um consumo diário estimado de 24,2 g de lisina digestível.

Fifty barrows with high genetic potential for lean gain and 60.5 ± 1.58kg of average initial live weight were used in a study to evaluate different lysine levels on performance and carcass traits. A randomized blocks experimental design, with five treatments, five replicates and two animals per replicate was used. Treatments consisted in five digestible lysine levels (0.600; 0.700; 0.800; 0.900; e 1.000%) obtained with the variation of corn and soybean meal proportion. Animals were kept in the experiment until they reached 95.8 + 2.64kg of final live weight. Lysine levels had a quadratic effect on feed conversion and feed conversion in muscle, which improved to the level of 0.85 % digestible lysine , and lean meat yield , which increased up to 0.840 % digestible lysine.The daily lysine intake increased linearly with the elevation of dietary levels of lysine. There was no effect of treatments on weight gain, feed intake, carcass traits, carcass yield, fat yield, and ham yield. It was concluded that barrows from 60 to 95 kg require 0.850% of total lysine, corresponding to a digestible lysine estimated intake of 24.2 g/day.

Dois experimentos foram conduzidos para determinar os efeitos da energia líquida (EL) da ração no desempenho e nas características de carcaça de suínos, recebendo dietas com proteína bruta reduzida (PB). Os suínos (60,0±1,05kg, Exp. 1, 93,0±1,56kg, Exp. 2) foram distribuídos em delineamento de blocos casualizados, com três tratamentos. O Exp. 1 teve seis baias/tratamento e o Exp. 2 teve 8 baias/tratamento e todas as baias tiveram 2 animais. Os tratamentos foram: 199g kg-1 PB e 2566kcal kg-1 NE, 155g kg-1 PB e 2.631kcal kg-1 NE, 155g kg-1 PB e 2.566kcal kg-1 NE no Exp. 1, e 180g kg-1 PB e 2588kcal kg-1 NE, 145g kg-1 PB e 2638kcal kg-1 NE, 145g kg-1 de PB e 2588kcal kg-1 NE, no Exp. 2. No Exp.1, a ração com 155g kg-1 PB e 2566kcal kg-1 EL resultou em maior GPD. Não houve efeito dos níveis PB ou EL sobre os demais parâmetros. No Exp. 2, os melhores resultados de CRD e GDP foram obtidos com 145g kg-1 PB e 2588kcal kg-1 EL. Os suínos alimentados com a dieta com 180g kg-1 PB e 2.588kcal kg-1 NE apresentaram menor quantidade de carne na carcaça. Não houve efeito do conteúdo de PB ou EL da ração na espessura de toucinho. A ração contendo 155g kg-1 PB e 2.566kcal kg-1 NE resultou em maior GPD de suínos dos 60 aos 95kg. Dos 95 aos 120kg, a dieta com 145g kg PB e 2588kcal kg-1 EL resultou em maior GPD e carne na carcaça.

Two experiments were conducted to determine the effects of dietary net energy content (NE) on performance and carcass traits of finishing barrows fed low-crude protein (CP) diets. Pigs (60.0±1.05kg, Exp. 1, 93.0±1.56kg, Exp. 2) were allotted in a randomized block design to 3 dietary treatments. Exp. 1 had 6 pens treatment-1 and Exp. 2 had 8 pens treatment-1 and all pens had 2 pigs. The treatments were: 199g kg-1 CP and 2566kcal kg-1 NE, 155g kg-1 CP and 2631kcal kg-1 NE, 155gk g-1 CP and 2566kcal kg-1 NE in Exp. 1, and 180g kg-1 CP and 2588kcal kg-1 NE, 145g kg-1 CP and 2638kcal kg-1 NE, 145g kg-1 CP and 2588kcal kg-1 NE, in Exp. 2. In Ep.1, except for average daily gain (ADG) there was no effect of dietary CP or NE on any other parameter evaluated. The diet with 155g kg-1 CP and 2566kcal kg-1 NE resulted in greatest ADG. In Exp. 2, the greatest results of ADFI and ADG were obtained with 145g kg-1 CP and 2588kcal kg-1 of NE. Pigs fed the diet with 180g kg-1 CP and 2588kcal kg-1 NE had less carcass meat. There was no effect of dietary CP or NE on backfat. The CP diet containing 2566kcal kg-1 NE resulted in greatest ADG of 60- to 95-kg barrows. For 95- to 120-kg barrows the diet with 145gk g-1 CP and 2588kcal kg-1 of NE resulted in greatest ADG and carcass meat.

Analisar composição corporal é relevante para caracterizar necessidades nutricionais e fase de terminação de peixes. Objetivou-se estudar a relação entre variáveis ictiométricas (peso, comprimentos total e padrão, densidade e rendimentos), bromatológicas (gordura, proteína, cinza e umidade) e aquelas da análise por bioimpedância ou BIA (resistência, reatância, ângulo de fase e índices de composição), no híbrido tambatinga (Colossoma macropomum x Piaractus brachypomus). Em um viveiro não fertilizado, 520 juvenis foram cultivados com ração comercial. Com idade de 136 dias após a eclosão dos ovos, 37,69 g de peso, 12,96 cm de comprimento total, 15 peixes, colhidos ao acaso, foram anestesiados (eugenol) e submetidos à primeira de quatorze avaliações quinzenais (BIA e biometria). Após eutanásia foram dissecados e pesados: carcaça inteira com cabeça, filé e pele (CICFP), filé com pele (FCP) e resto da carcaça com cabeça (CCC). Juntos, FCP e CCC foram moídos e homogeneizados para análise bromatológica. Estimativas da composição corporal e de rendimentos do tambatinga, com modelos incluindo variáveis ictiométricas e da BIA, apresentaram coeficientes de correlação entre 0,81 (para o rendimento do FCP) e 1,00 (para cinzas totais). Analogamente, modelos com a inclusão apenas de variáveis da BIA mostram coeficientes de correlação entre 0,81 (rendimento do FCP e do CCC) e 0,98 (para cinzas totais). Portanto, no tambatinga, a técnica da BIA possibilita a estimativa do rendimento de filé com pele e composição corporal (umidade, gordura, cinza e proteína). Os melhores modelos agregam variáveis ictiométricas e da BIA.

Body composition analysis is relevant to characterize the nutritional requirements and finishing phase of fish. The aim of this study was to investigate the relationship between ichthyometric (weight, total and standard length, density and yields), bromatological (fat, protein, ash and water content) and bioelectrical-impedance-analysis (BIA) (resistance, reactance, phase angle and composition indexes) variables in the hybrid tambatinga (Colossoma macropomum × Piaractus brachypomus). In a non-fertilized vivarium, 520 juveniles were housed and fed commercial rations. Then, 136 days after hatching (DAH), 15 fish with an average weight of 37.69 g and average total length of 12.96 cm were randomly chosen, anesthetized (eugenol) and subjected to the first of fourteen fortnightly assessments (BIA and biometry). After euthanasia, the following parts were weighed: whole carcass with the head, fillet, and skin (WC); fillet with skin (FS); and the remainder of the carcass with the head (CH). Together, FS and CH were ground and homogenized for the bromatological analyses. Estimates of the body composition and yields of tambatinga, with models including ichthyometric and BIA variables, showed correlation coefficients ranging from 0.81 (for the FS yield) to 1,00 (for the total ash). Similarly, models that included only BIA variables had correlation coefficients ranging from 0.81 (FS and CH yields) to 0.98 (for the total ash). Therefore, in tambatinga, the BIA technique allows the estimation of the yield of the fillet with skin and the body composition (water content, fat, ash, and protein). The best models combine ichthyometric and BIA variables.

The objective of this study was to analyze the effect of whole cassava root scrapings at different levels in diets for broilers in the period of 22 to 42 days of age in high-temperature environments on performance, as well as to evaluate the metabolizability of dry matter (DM), crude protein (CP) and gross energy (GE) and nitrogen balance. A total of 400 male Ross broilers were used for evaluation of performance and 80 birds of the same strain were used in the metabolism experiment. The design was of randomized block with five treatments and four replications. The experimental unit was represented by twenty birds on the performance evaluation and four birds were housed in metabolic cages for the metabolism evaluation. The treatments consisted of diets containing inclusion levels of cassava root scrapings (0, 50, 100, 150 and 200 g/kg), formulated to meet the nutritional requirements accordingly to each phase of the birds. Whole cassava root scrapings can be included in diets for 22 to 42 day-old broiler chickens, at a level between 118.75 and 200 k/kg, in environments of high temperatures, with positive interference on weight gain and feed conversion, without affecting the coefficient of metabolizability of dry matter, crude protein, gross energy and nitrogen balance, or carcass characteristics, such as yields of main cuts and metabolically active organs of the birds.

A pesquisa foi realizada para avaliar o efeito dos níveis de inclusão da raspa integral da raiz da mandioca sobre o desempenho produtivo de frangas da linhagem Ross no período de um a 42 dias de idade, bem como as características da carcaça aos 42 dias de idade. O delineamento experimental foi de blocos ao acaso, com cinco tratamentos e quatro repetições. A unidade experimental foi representada por 20 aves, alojadas em cada box. Os tratamentos consistiram de rações que continham diferentes níveis de inclusão da raspa da raiz integral de mandioca (0; 5; 10; 15 e 20%), formuladas para atender as exigências nutricionais de acordo com cada fase da criação, e foram utilizados quatro programas de alimentação. A inclusão da raspa integral não afetou o ganho de peso e a viabilidade da criação de frangas de corte no período de um a 42 dias, para ganho de peso e viabilidade da criação. No entanto, o consumo de ração e a conversão alimentar foram influenciados pelos níveis de inclusão da raspa integral de mandioca. Pode-se utilizar em dietas balanceadas de frangas de corte, no período de 1 a 42 dias, até o nível de 6,77%, sem comprometer as características da carcaça e o rendimento dos principais cortes e dos órgãos comestíveis.

This research was developed to evaluate the effect of inclusion the levels of integral scraping of cassava roots on performance and carcass characteristic of pullets of Ross strain, in the period from 1 to 42 days. The experimental design was a randomized block with five treatments and four replications, being the experimental unit represented by twenty birds, housed in each box. The treatments consisted of diets containing different levels of inclusion of integral scraping of cassava root (0; 5; 10; 15 and 20%), formulated to attend the nutritional requirements according to each phase of the birds, using four feeding programs. The inclusion of scrapings of cassava root in diets did not affect the weight gain and feasibility of housing of pullets in the period from 1 to 42 days. However, feed intake and feed conversion were affected with inclusion levels scraping cassava root. The scrapings of cassava root can be used in diets of pullets, in the period from 1 to 42 days in levels up to 6.77%, without compromising carcass characteristics and main cuts and edible organs.

This experiment was conducted to determine the requirement of available phosphorus (aP) for pigs kept in hot environment. Seventy-two pigs (36 castrated males and 36 females) with initial weight of 15.10±0.31 kg were allotted in a completely randomized block design with six treatments (0.107, 0.214, 0.321, 0.428, 0.535, and 0.642% of aP), six replicates and two pigs (1 castrated male and 1 female) per experimental unit. Pigs were kept in a hot environment with temperature of 34.1±0.8 ºC. The levels of aP influenced the daily weight gain, which increased quadratically up to the estimated level of 0.477%, and feed conversion, which improved quadratically up to the estimated level of 0.457%. The levels of aP also influenced the content of phosphorus in the bone, which increased quadratically up to the estimated level of 0.529%. The available phosphorus requirement of 15- to 30-kg pigs kept in a hot environment, for the best results of daily weight gain, feed conversion and bone parameters are 0.477, 0.457, and 0.529%, corresponding to the estimated daily available phosphorus intakes of 4.75; 4.55 and 5.27 g, respectively.

Este estudo foi realizado para avaliar níveis de lisina digestível para suínos dos 30 aos 60 kg mantidos sob estresse por calor. Utilizaram-se 70 suínos machos castrados mantidos em ambiente a 30ºC e outros 70 em ambiente a 34ºC, distribuídos em delineamento de blocos ao acaso, com cinco tratamentos (0,83; 0,93; 1,03; 1,13 e 1,23% de lisina digestível), sete repetições e dois animais por unidade experimental. O ganho de peso diário dos animais mantidos a 30ºC aumentou até o nível de 1,04% de lisina digestível, mas a 34ºC não variou. O consumo de ração diário dos animais a 30 e a 34ºC não variou com os níveis de lisina. O consumo de lisina diário dos animais, em ambos os ambientes, aumentou de acordo com o nível de lisina da ração. A 30ºC, a conversão alimentar melhorou até o nível de 1,07% de lisina, enquanto a 34ºC não variou entre os níveis de lisina. Independentemente da temperatura, a eficiência de utilização de lisina reduziu conforme aumentaram os níveis de lisina e foi 4,4% pior no ambiente com temperatura mais elevada. A deposição de proteína na carcaça dos animais no ambiente a 30ºC aumentou até o nível de 1,05% de lisina, mas não variou no ambiente a 34ºC. A 30ºC, a deposição de gordura reduziu até o nível de 1,08% de lisina, enquanto a 34ºC, aumentou até o nível de 1,08% e foi, em média, 25,6% menor que a 30ºC. Os níveis de triiodotironina e tiroxina foram 35 e 30%, respectivamente, menores nos animais mantidos em ambiente a 34ºC, em que a frequência respiratória e temperatura retal também foram mais altas que as observadas nos animais mantidos a 30ºC. Os níveis de 1,04 e 0,83% de lisina digestível proporcionam maior ganho de peso e deposição de proteína em suínos mantidos, respectivamente, em ambientes a 30 e 34ºC.

This study was conducted to evaluate levels of digestible lysine for pigs at 30 to 60 kg kept under heat stress. It was used 70 castrated animals kept in environment at 30ºC and others 70 kept at 34ºC, distributed in a randomized block design, with five treatments (0.83, 0.93, 1.03, 1.13 and 1.23% digestible lysine), and seven repetitions with two animals per experimental unit. The daily weight gain of the animals kept at 30ºC increased up to 1.04% of digestible lysine, whereas it did not change at 34ºC. Feed daily intake of animals at 30ºC and 34ºC did not change with levels of lysine. Daily lysine intake of animals, in both environments, increased according to the level of lysine in the diet. At 30ºC, feed conversion improved up to the level of 1.07% lysine, whereas at 34ºC, it did not vary among lysine levels. Regardless of the temperature, use efficiency of lysine decreased as levels of lysine increased and it was 4.4% worse in the environment with higher temperature. Protein deposition in carcass in the 30ºC environment increased up to the level of 1.05% lysine, but it did not change at 34ºC. At 30ºC, fat deposition decreased down to 1.08% lysine, whereas in the 34ºC environment, it increased up to 1.08%, and it was on average 25.6% lower than at 30ºC. Levels of triiodothyronine and thyroxine were 35 and 30%, respectively, which was lower in animals kept in the 34ºC environment, where respiratory rate and rectal temperature were higher than those observed in animals kept in the environment at 30ºC. The levels of 1.04 and 0.83% of digestible lysine provide greater weight gain and protein deposition in pigs kept in environments at 30ºC and 34ºC, respectively.

Foram avaliados o desempenho e a composição muscular da carcaça de alevinos de tambatinga, com peso inicial de 6,521 ± 0,300 g, alimentados com dietas isoenergéticas, isocálcicas e isofosfóricas contendo 40, 37, 34, 31 ou 28% de proteína bruta. Os peixes foram mantidos durante 40 dias em tanques de polietileno, com sistema de recirculação de água. No início e final do experimento, os peixes foram pesados e os dados utilizados para avaliação do ganho de peso diário, consumo diário de ração, conversão alimentar aparente, índice de conversão alimentar, consumo diário de proteína, taxa de crescimento específico e taxa de eficiência proteica. No início e final do experimento, foram selecionadas amostras de peixes para análise da composição muscular, e os resultados utilizados para avaliar a eficiência de retenção de proteína e a proporção de proteína e extrato etéreo no ganho de peso. Entre os parâmetros de desempenho, os níveis de PB influenciaram apenas o consumo de proteína e a taxa de eficiência proteica, com efeito linear. Os teores de proteína bruta, a proporção de proteína no ganho de peso e eficiência de retenção de proteína no músculo dos alevinos de tambatinga aumentaram linearmente com a redução de proteína bruta na dieta, enquanto o teor de extrato etéreo e sua proporção no ganho de peso diminuíram. O nível de 28% de PB, quando há suplementação com aminoácidos, pode ser utilizado em dietas para alimentação dos alevinos de tambatinga, pois não prejudica seu desempenho.

This study was developed to evaluate the performance and carcass composition of tambatinga fingerlings, with initial weight of 6.521 ± 0.300 g, fed with isocaloric, isocalcic and isophosphoric diets (40, 37, 34, 31 and 28% of CP). Fish were cultivated for forty days in polyethylene tanks, with water recirculation system. Fishes were weighed at the beginning and at the end of the trial and the data were used for evaluation of weight gain, feed intake, apparent feed conversion, index of feed conversion, protein intake, specific growth rate and protein efficiency rate. At the beginning and end of the experiment, samples of fishes were selected for analysis of muscle composition, and the results were utilized to assess protein retention efficiency and proportion of protein and ethereal extract at weight gain. Among the performance parameters, crude protein levels influenced only protein intake and protein efficiency rate, with linear effect. Crude protein amount, proportion protein on weight gain and protein retention efficiency of the tambatinga fingerling's muscle, increased linearly with protein reduction in the diet, whereas ethereal extract and its proportion on weight gain decreased. It was concluded that the diet with 28% of protein can be used for tambatinga fingerlings without affecting performance.

In order to evaluate the effects of dietary digestible lysine levels on performance and carcass traits of two genetic lines of pigs selected for meat deposition, from 60 to 100 days of age, a total of 120 crossbred barrows, with initial average body weight of 25.42 ± 2.08 kg were used. Pigs were allotted in a complete randomized block design, within a 4 × 2 factorial arrangement (four digestible lysine levels: 0.90, 1.00, 1.10, and 1.20%, and two genetic lines: A and B), with five replicates and three pigs per pen, which was the experimental unit. There was no interaction between genetic and digestible lysine levels for any variable of performance and carcass traits assessed. There was also no effect of digestible lysine levels in feed intake, body weight gain, and feed conversion. Digestible lysine intake of pigs increased linearly with increasing digestible lysine levels in the diets. Except for carcass yield that increased quadratically up to 1.04% estimate level of digestible lysine, there was no effect of lysine levels on the other carcass traits assessed (loin and ham yield, and amount of meat in the carcass). The digestible lysine level of 0.90%, corresponding to an estimated daily intake of 19.10 g, meets the requirements of castrated male pigs selected for meat deposition from both genetic lines, from 60 to 100 days of age.

Avaliou-se o efeito de níveis de lisina digestível sobre o desempenho e a composição de carcaça de suínos machos castrados de alto potencial genético para deposição de carne. Foram utilizados 80 animais com peso inicial de 95,55 ± 1,04 distribuídos em delineamento experimental de blocos ao acaso, com cinco dietas (0,540; 0,642; 0,744; 0,846 e 0,948% de lisina digestível), oito repetições e dois animais por unidade experimental. As dietas experimentais e água foram fornecidas à vontade durante todo o período experimental. Os níveis de lisina digestível não influenciaram o consumo de ração diário e o peso de carcaça dos animais. O ganho de peso diário e a conversão alimentar melhoraram de forma quadrática até os níveis de lisina digestível estimados de 0,803 e 0,817%, respectivamente. Foi observado efeito linear crescente dos tratamentos sobre o consumo diário de lisina e sobre a quantidade de carne. Embora, a deposição diária de carne tenha aumentado de forma linear, o modelo LRP foi o que melhor se ajustou aos dados que permaneceram em um platô a partir do nível de lisina digestível de 0,803%. Os níveis de lisina digestível influenciaram a espessura de toucinho P2 dos animais que reduziu de forma linear. O nível de lisina digestível de 0,803%, que corresponde a consumo de 24,60 g/dia de lisina digestível, proporciona os melhores resultados de ganho de peso e deposição de carne, enquanto o nível de 0,817%, correspondente a consumo de 25,03 g/dia de lisina, proporciona melhor conversão alimentar e o de 0,948%, correspondente a consumo de 29,09 g/dia de lisina digestível, promove maior deposição de carne e espessura de toucinho em suínos machos castrados na fase dos 95 aos 125 kg.

This work evaluated levels of digestible lysine on performance and carcass composition of barrows with high genetic potential for meat deposition. It was used 80 animals with initial body weight of 95.55 ± 1.04 kg, distributed in a completely randomized block design, with 5 diets (0.540; 0.642; 0.744; 0.846 and 0.948% of digestible lysine), eight replicates and two animals per experimental unit. The experimental diets and water were provided ad libitum throughout the experimental period. Digestible lysine levels did not change daily feed intake and carcass weight of the animals. Daily weight gain and feed conversion improved in a quadratic way up to the estimated levels of 0.803 and 0.871% of digestible lysine, respectively. It was observed an increasing linear effect of the treatments on daily lysine intake and amount of meat. Although daily meat deposition had increased in a linear way, the LRP was the model that best adjusted to the data which remained on a plateau from 0.803% of digestible lysine level. The levels of digestible lysine influenced the P2 backfat thickness of the animals which decreased in a linear way. The digestible lysine level of 0.803%, corresponding to an intake of 24.60 g/day of digestible lysine provides the best results of weight gain and meat deposition whereas the level of 0.817% corresponding to an intake of 25.30 g/day of lysine provides the best result of feed conversion, and the digestible lysine level of 0.948% corresponding to an intake of 29.09 g/day of digestible lysine provides the best results of meat deposition and backfat thickness of barrows from 95 to 125 kg.