ABSTRACT Several empirical models were proposed to predict feed intake (FI) of growingfinishing pigs reared under high environmental temperatures. However, these models have not been evaluated under conditions different from those in which they were developed. Twelve empirical models were evaluated using a database built after systematic literature review (observed data: 28 studies in which the FI was evaluated in pigs under high environmental temperatures). Model accuracy was assessed using the mean squared of prediction error (MSPE). Analyses were performed considering two scenarios: (1) general population, where all observed data were used in the simulation; (2) reference population, where data were filtered in order to simulate only scenarios with environment (temperature range) and animals (body weight and sex) similar to that used in the model development. Six models estimated FI values similar (p > 0.05) to those observed in the general population, while four models produced estimates similar to the observed values in the reference populations. Most models were more accurate when they were simulated using the reference population than when the simulation considered the general database. Moving the simulation from the general database to the reference population reduced up to 98 % of the MSPE, depending on the equation. Empirical models allow to accurately predict FI of growing-finishing pigs exposed to high environmental temperatures, especially in scenarios similar to the ones used for model development. Thus, population characteristics (body weight and sex) and environment (temperature range) must be considered in the model assessment.

ABSTRACT A nitrogen balance test was performed to evaluate the individual responses of growing pigs to threonine intake. Eight commercial barrows were used (body weight ranging from 15 to 20 kg). A dose-response study was performed, in which the threonine supply increased in seven equidistant steps (the seven dietary threonine levels ranged from 50 to 120% of the requirements) every three days for each pig. The levels of all other amino acids were 20% higher than the tested amino acid. Nitrogen retention as a function of threonine intake was calculated per individual and per group (NLIN and NLMixed, respectively) using a linear plateau model. The highest break point value was 42.42 g of threonine intake (the most demanding individual), whereas the lowest value was 34.16 g (the least demanding individual), corresponding to a difference of 19%. In terms of N retention, the highest plateau value was 66.71 g and the lowest was 49.48 g, with a difference of 25%. There was no significant correlation between slope and plateau values or between slope and break point values. When using the model in which all parameters were random effects, the variations in threonine intake and nitrogen retention were 1.68±1.30 and 0.01±0.10 g, respectively, and no variance in the slope of the curve was detected. The average daily threonine intake values for the maximum response obtained in the group, as calculated by the NLIN and NLMixed procedures, were 13.96 and 14.02 g/day, respectively. The threonine intake for the maximum N retention between individuals ranged from 34.16 to 42.42 g, corresponding to a difference of 19%. The current recommended intake to optimize N retention is 14.02 g/day. The group responses obtained by the NLMixed procedures are very similar to those estimated by the NLIN procedure (all individuals).

Foi realizado um experimento para verificar o impacto da densidade de alojamento em frangos de corte (11,08 e 13,20 aves m-2) sobre o desempenho, rendimento de cortes, umidade da cama e frequência de lesões por pododermatite no período de cinco a 45 dias de idade. Foram utilizados 476 pintos da linhagem Cobb 500(r) com um dia de idade, distribuídos em um delineamento experimental inteiramente casualizado, empregando duas densidades (aves m-2) e sete repetições por tratamento, 14 unidades experimentais. Observou-se que as aves alojadas em menor densidade (11,08) apresentaram maior consumo de ração (p < 0,05), porém, sem afetar o ganho de peso e a conversão alimentar. O rendimento das partes não foi influenciado pelos tratamentos (p > 0,05). Foi verificado efeito significado (p < 0,05) sobre a umidade da cama na maior densidade (3,20), apresentando maior umidade (p < 0,05) aos 28 e aos 35 dias de idade das aves. Observou-se maior incidência por pododermatite em aves alojadas na maior densidade (3,20). Conclui-se que o aumento da densidade de alojamento de 11,08 para 13,20 aves m-2, não afeta o desempenho zootécnico, rendimento da carcaça e cortes. Porém, promoveu aumento na umidade na cama, assim como a maior incidência de pododermatite de grau 1 foi observada na densidade de 13,20 aves m-2.

The effect of stocking density in broiler chickens (11.08 and 13.20 birds m-2), between 5 and 45 days of age, was assessed with regard to performance, cut yield, litter moisture and frequency of pododermatitis injuries. Further, 476 one-day chicks Cobb 500(r) were distributed in a completely randomized design at two densities (birds m-²), with seven replications per treatment in 14 experimental units. Birds housed at a lower density (11.08) increased feed intake (p < 0.05), without any effect on weight gain and feed conversion. Retail yields were not influenced (p > 0.05) by treatments. In the case of higher density (3.20) the litter showed higher moisture content (p < 0.05) at 28 and 35 days of age. There was a higher occurrence of pododermatitis in birds housed at a density of 13.20 birds m-2. Results show that increased housing density from 11.08 to 13.20 birds m-2 does not affect growth performance, carcass yield and cuts. However, a housing density of 13.20 birds m-2 increased litter moisture and provided a higher occurrence of grade I pododermatitis.

A semente do maracujá é um subproduto da extração da polpa do maracujá, podendo ser utilizado na alimentação dos suínos. Foram conduzidos dois experimentos (digestibilidade e desempenho), objetivando avaliar a utilização do farelo da semente de maracujá na alimentação de suínos em crescimento e terminação. Inicialmente foi realizado um ensaio de digestibilidade com suínos em crescimento e terminação, em que o farelo da semente de maracujá (FSM) substituiu a ração referência (0% FSM) em níveis de 4, 8, 12 e 16%. Foram utilizados 30 suínos, machos castrados, com peso vivo médio inicial de 36,85±4,19. O FSM apresentou ED e EM de 3.244 e 3.223 Mcal/kg, respectivamente. No ensaio de desempenho, foram utilizados 150 suínos, sendo 75 na fase de crescimento e 75 na fase de terminação, com peso vivo inicial de 30,63±1,49 e final de 60,38±4,75 kg e 60,40±1,50 e 90,02±4,84 kg, respectivamente. Foram utilizadas cinco dietas, sendo quatro níveis de inclusão do FSM (4, 8, 12 e 16%) e uma ração testemunha (0% do FSM). Os níveis do FSM não influenciaram (P>0,05) as variáveis de desempenho. Na fase de crescimento, os níveis séricos de colesterol aumentaram linearmente (P<0,05) com os níveis de inclusão do FSM. As variáveis quantitativas de carcaça e qualitativas da carne não foram influenciadas (P>0,05) pelos níveis crescentes do FSM nas dietas. Conclui-se que o FSM pode ser utilizado em até 16% em dietas de suínos em crescimento e terminação.

The passion fruit seed is a byproduct of the extraction of the passion fruit pulp and can be used for feeding to pigs. Two experiments were conducted (digestibility and performance) to evaluate the use of the passion fruit seed meal in feed for growing and finishing pigs. A digestibility trial was conducted with growing and finishing pigs, in which the passion fruit seed meal (PSM) replaced the reference diet (0% PSM) in levels of 4, 8, 12 and 16%. Thirty barrows were used with average weight of 36.85±4.19. The PSF showed DE and ME of 3.244 and 3.223 Mcal/kg, respectively. In the performance trial, were used 150 pigs, which 75 in the growing phase and 75 pigs in the finishing, with initial body weight of 30.63±1.49 and final of 60.38±4.75 kg and 60.40±1.50 and 90.02±4.84 kg, respectively. Five diets were used, with four inclusion levels of PSM (4, 8, 12 e 16%) and one control diet (0% of PSM). The PSM levels did not influence (P>0.05) the performance variables. In the growing pigs, serum levels of cholesterol increased linearly with (P<0.05) inclusion levels of PSM. Quantitative of carcass traits and meat quality were not affected (P>0.05) by increasing levels of PSM in the diets. We conclude that the PSM can be used up to 16% in growing and finishing pigs diets.