RESUMO -Foram determinados os valores de energia metabolizável aparente (EMA) e energia metabolizável aparente corrigida pelo balanço de nitrogênio (EMA n ) e os coeficientes de metabolizabilidade aparente (CMA) e aparente corrigida pelo balanço de nitrogênio (CMA n ) de cinco alimentos. Cento e vinte pintos de corte com 21 dias de idade foram distribuídos aleatoriamente em seis tratamentos (uma ração-referência e cinco rações-teste) e quatro repetições de cinco aves. Os alimentos avaliados foram: resíduo de incubatório (RI), farinha de penas (FP), farinha de vísceras de aves (FVA) e duas farinhas de carne e ossos (FCO 1 e FCO 2). Os alimentos substituíram em 20% a ração-referência. Para determinação dos valores de EMA e EMA n , foi utilizado o método tradicional de coleta total de excretas. Energy Values of Animal By-Products for PoultryABSTRACT -The apparent metabolizable energy (AME), nitrogen corrected apparent metabolizable (AME n ), apparent metabolizability coefficient (AMC) and nitrogen corrected apparent metabolizability coefficient (AMC n ) of five feedstuffs were determined. The feedstuffs investigated were: hatchery by-product meal (HM), feather meal (FM), poultry viscera meal (PVM) and two meat and bone meal (MBM 1 and MBM 2) of different origin. The values of AME and AME n were determined by the total excreta collection method. One hundred and twenty broiler chicks at 21 days old were randomly allotted to six treatments (one basal reference diet and five test diets), with four replications with five birds per experimental unit. The feedstuffs replaced 20% reference diet. The AME values expressed in kcal/kg as-fed basis for feedstuffs HM, FM, PVM, MBM 1 and MBM 2 were: 1.495, 2.774, 2.676, 2.567 and 1.652 and the AME n values were: 1.301, 2.758, 2.384, 2.307 and 1.488, respectively. According to AME, AME n and gross energy (GE) values, the AMC and AMC n were calculated for xHM, FM, PVM, MBM 1 and MBM 2 (8,79%), that showed the respective values of 0.09, 55.49, 69.31, 67.71 and 51.14 for AMC and 52.26, 55.18, 61.75, 60.85 and 46.07 for AMC n .

RESUMO -Foram utilizados 960 pintos, metade machos e metade fêmeas, no período de 1 a 21 dias idade, com peso inicial médio de 42,5 e 42,1g, respectivamente. O delineamento experimental utilizado foi em blocos casualizados, com seis tratamentos, dois sexos, quatro repetições por sexo e vinte aves por unidade experimental. Os tratamentos consistiram de uma dieta basal deficiente em fósforo (0,150%), suplementada com fósforo disponível, provenientes do fosfato bicálcico (0,0; 0,10; 0,20; 0,30; 0,40; e 0,50%). As variáveis avaliadas foram ganho de peso (GP), consumo de ração (CR), conversão alimentar (CA), resistência dos ossos à quebra (ROQ), cinzas (CO) e fósforo no osso (PO). As exigências em fósforo disponível foram estimadas por intermédio dos modelos de regressão polinomial e LRP. As suplementações com fósforo disponível influenciaram o GP, CR, CA, ROQ, CO e PO, tanto para os machos como para as fêmeas. As estimativas de exigências de P-disp variaram de 0,259 (0,085%/Mcal de EM) a 0,559% (0,184%/Mcal de EM), para os machos, e de 0,307% (0,092%/Mcal de EM) a 0,575% (0,190%/Mcal de EM) para as fêmeas. Entretanto, considerando as respostas biológicas, para as variáveis de desempenho e características ósseas, pode-se sugerir que a exigência de fósforo disponível, para frangos de corte machos e fêmeas, de 1 a 21 dias de idade, é de 0,45 ou 0,148% de Pdisp/Mcal de EM. Palavras-chave: exigência de fósforo disponível, frangos, fase inicial Available Phosphorus Requirement of Male and Female Broilers from 1 to 21 Days of AgeABSTRACT -Ninety and sixty Hubbard one-day-old broilers chicks, half male and half female, were used at the initial phase, from 1 to 21 days of age, with initial weight of 42.5 and 42.1g, respectively. The chicks were allotted to a randomized block design, with six treatments, two sexes, four replicates per sex and twenty animals per experimental unity. The treatments consisted on deficient basal diet in available phosphorus (.15%), supplemented with available phosphorus from dicalcium phosphate (0, 0.10, 0.20, 0.30, 0.40, and 0.50%). The weight gain (GP), feed intake (CR), feed: gain (CA), bone fracture resistance (BFR), ashes (AO) and phosphorus in the bone (PO) were the evaluated variables. The available phosphorus requirements were estimated by means of the regression polynomial and linear response plateau models. The supplemented levels of available phosphorus affected the GP, CR, CA, BFR, AO and PO, for males and females. The requirement estimates of available phosphorus ranged from 0,259 (.089%/Mcal ME) to .559%

-Two experiments were carried out to evaluate the reduction of crude protein (CP) in diets supplemented with synthetic amino acids for piglets of 15 to 30 kg. In the performance assay (Exp I), 60 piglets with initial weight of 15.34±0.87 kg and final weight of 30.08±1.59 kg were distributed in a randomized block design with six replicates, five treatments and two animals per experimental unit. The treatments consisted of five diets in which the CP was reduced by 1.5 percentage points, resulting in low-protein diets (19.24, 17.74, 16.24, 14.74 and 13.24%), meeting the requirements of amino acids with inclusion of L-lysine, DL-methionine, L-threonine, L-tryptophan, L-valine and L-isoleucine. The average daily gain and feed conversion according to the Linear Response Plateau model (LRP) were estimated at 14.23 and 14.79% of CP, respectively. As the CP levels were reduced, there was an increase in the essential:non-essential amino acids ratio. The plasma urea concentration decreased linearly, indicating that there was a better use for amino acids with the CP reduction. In the nitrogen balance (Exp II), 30 crossbred barrow piglets with average weight of 21.69±4.46 kg were housed in metabolic cages, distributed in a completely randomized design with five treatments and six replicates, and the experimental unit consisted of a piglet. The biological protein value in the diets remained above the ideal (70%), in which the level of 13.24% CP corresponded to the highest value. There was no difference in levels of urea in blood and urine. Reduction of protein levels is efficient in decreasing the pollution effect in the excreta, with lower nitrogen excretion in feces and urine.

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Four experiments were conducted to estimate the optimal standardized ileal digestible ( SID ) level of branched-chain amino acids in low-protein diets during the starter, grower, and finisher periods, using the response surface methodology, and to study their effects on performance and mRNA expression of genes involved in the mechanistic target of rapamycin ( mTOR ) pathway of broiler chickens from 8 to 21 D of age. In experiments 1, 2, and 3, a total of 1,500 Cobb male broiler chickens were assigned to 15 diets of a central composite rotatable design ( CCD ) of response surface methodology containing 5 levels of SID Leu, Val, and Ile with 5 replicate pens of 20 birds each. A 3-factor, 5-level CCD platform was used to fit the second-order polynomial equation of broiler performance. In experiment 4, a total of 540 8-day-old Cobb male broiler chickens were distributed in a completely randomized 2 x 3 x 3 factorial arrangement with 2 SID Leu levels (1.28 or 1.83%), 3 SID Val levels (0.65, 0.90, or 1.20%), and 3 SID Ile levels (0.54, 0.79, or 1.09%) for a total of 18 treatments with 5 replicate cages of 6 birds each. High Leu levels impaired (P < 0.05) gain:feed when birds were fed marginal Val or Ile diets. However, gain:feed was restored when both Val and Ile were supplemented to reach adequate or high levels. High Leu levels increased ( P < 0.05) mRNA expression of S6K1 and eEF2 genes only in birds fed high Ile levels. Dietary SID Leu, Val, and Ile levels required for gain:feed optimization in low-protein diets were estimated at 1.37, 0.94, and 0.87% during the starter period; 1.23, 0.82, and 0.75% during the grower period; and 1.15, 0.77, and 0.70% during the finisher phase, respectively. Higher Val and Ile levels are required to optimize the effect of Leu supplementation on mRNA expression of mTOR pathway genes in the pectoralis major muscle of broilers from day 1 to 21 after hatch.

Two experiments were performed to study the interaction between the standardized ileal digestible (SID) leucine (Leu) and valine (Val) levels on the mRNA expression of genes involved in the mechanistic target of rapamycin (mTOR) pathway (experiment I) and determine the requirement of these amino acids in low-protein diets, and their effects on performance, serum parameters and muscle fiber diameters of broilers (experiment II) from day 1 to day 21 post hatch. Broiler chickens were distributed in a completely randomized design in a 3 × 3 and 5 × 5 factorial arrangement for a total of 9 and 25 treatments in experiments I and II, respectively. There was no (P > 0.05) interaction between the SID Leu and Val levels on mRNA expression of mTOR, S6 kinase 1 (S6K1), 4E-binding protein-1 (4EBP1), eukaryotic elongation factor 2 (eEF2), and insulin-like growth factor-1 (IGF-1) genes in pectoralis major muscle. Leucine supplementation increased (P < 0.05) mRNA expression of mTOR and S6K1 genes in muscle tissue, whereas Val supplementation did not affect (P > 0.05) mRNA expression of the genes investigated. Interaction was observed (P < 0.05) between dietary Leu and Val levels on feed intake and gain:feed. Leucine supplementation may stimulate mRNA expression of mTOR and S6K1 genes in pectoralis major muscle of broilers from day 1 to day 21 post hatch. The SID Leu and Val levels required for the optimization of feed intake, weight gain, and gain:feed in low-crude protein diets for broiler chickens from day 1 to 21 post hatch were estimated at 1.29% and 0.96%, 1.28% and 0.92%, and 1.27% and 0.91%, respectively; however, these requirements may be greater to maximize muscle fiber growth.

RESUMO. O objetivo do trabalho foi determinar a composição química e energética de seis diferentes farinhas de carne e ossos, bem como desenvolver equações de predição da energia digestível e metabolizável, com base na composição química dos alimentos. Foram utilizados 28 suínos, mestiços, machos castrados, com peso médio inicial de 25,90 ± 1,95 kg, distribuídos em delineamento experimental de blocos ao acaso, com sete tratamentos, quatro repetições e um animal por unidade experimental. Os tratamentos consistiram de uma ração-referência e seis diferentes farinhas de carne e ossos, que substituíram em 20% a ração-referência. Os valores de energia digestível e metabolizável variaram de 1.717 a 2.908 kcal kg-1 e de 1.519 a 2.608 kcal kg-1 , respectivamente. As equações de predição da energia digestível e metabolizável que apresentaram maiores R 2 para a farinha de carne e ossos foram:

Glycerin is a major co-product resulting from biodiesel production, and it has been proposed as a highenergy source for use in swine diets. However, it is necessary to determine the nutritional value of neutral semi-purified glycerin (NSPG). In this study two experiments were carried out to determine the nutritional value, evaluated the performance and economic feasibility of starting piglets fed on neutral semi-purified glycerin. A digestibility trial (Experiment I) was conducted using 30 crossbred barrows with an initial average body weight of 42.91±1.58 kg. The glycerin levels used in the digestibility assay were 4, 8, 12 and 16% of the basal diet (corn + soybean meal based). The digestible energy (DE) and metabolizable (ME) energy values of glycerin were estimated by regression of DE and ME (kcal/kg) intake associated with glycerin vs. glycerin intake (kg). The values (as-fed-basis) of DE and ME (kcal/ kg) obtained were 3,298 and 2,531, respectively. In Experiment II, 100 piglets (50 gilts and 50 barrows) with BW = 15.14±0.06 to 30.28±0.65 were allotted in a randomized design using four inclusion levels (3.5, 7.0, 10.5 and 14%) of NSPG. There were ten replicates with two piglets per experimental unit. Additionally, a control diet containing no glycerin (0%) was formulated. The results show it is feasible to use up to 14% NSPG in piglet feed without impairing performance and plasma chemistry. Key words: Biodiesel, digestibility, glycerol, performance ResumoA glicerina é o principal coproduto da produção do biodiesel, e é proposta sua utilização como uma fonte de alto potencial energético na alimentação de suínos. No entanto é necessário determinar seu valor nutricional da glicerina semi-purificada neutralizada (GSPN). Neste estudo, foram conduzidos dois experimentos com o objetivo de determinar o valor nutricional, avaliar o desempenho e a viabilidade econômica de leitões alimentados com GSPN. O ensaio de digestibilidade (Experimento I) foi conduzido utilizando 30 suínos mestiços com peso vivo médio inicial de 42,91 ± 1,58 kg. Os níveis de substituição da ração referência pela glicerina foram 4, 8, 12 e 16%. Os valores de energia digestível (ED) e metabolizável (EM) das glicerinas foram estimados pela análise de regressão do consumo de ED e EM (kcal/kg) associada com a glicerina vs. consumo de glicerina (kg). Os valores de ED e EM (kcal/ kg), na matéria natural, obtidos foram de: 3.298 e 2.531 kcal/kg respectivamente. No experimento II, 100 leitões (50 fêmeas e 50 machos cadastros) com peso vivo inicial de 15,14±0,06 a 30,28±0,65 kg) foram distribuídos em delineamento de blocos casualizados, com quatro níveis de inclusão (3,5; 7,0;