ABSTRACT The objective of this study was to evaluate the effects of supplementation of two different enzymatic complexes, fibrolytic (NSPases) or amylolytic (EXP3066) enzymes, on growth performance, digestibility, behavior, and carcass characteristics of feedlot cattle. Thirty-six ½ Angus yearling bulls with an average initial weight of 391±5.0 kg were used in this experiment blocked by weight in a completely randomized design divided in three treatments: control, NSPases, and EXP3066. The basal diet was composed of 85% whole corn grain and 15% nucleus. NSPases increased average daily gain on days 63 and 84, and gain:feed ratio on days 42, 63, and 84. Total carcass weight and carcass daily gain were improved by 4.8% and up to 6.0% with EXP3066 and NSPases supplementations, respectively. The group that received NSPases supplementation showed even greater carcass feed efficiency when compared with animals in the control group. There was an increase in apparent dry matter digestibility and a decrease of fecal whole grain residual percentage with enzyme supplementation. Enzyme supplementation affected hot carcass weight and EXP3066 provided greater values for ribeye area and marbling compared with control. Exogenous enzymes improve performance and carcass traits in feedlot cattle fed high-grain diet.

ABSTRACT This study was carried out to evaluate the effect of different levels of standardized ileal digestible (SID) methionine + cystine (Met+Cys) and vitamin B6 supplementation on the performance, blood variables, and gene expression of enzymes involved in methionine metabolism in female pigs between 75 and 100 kg. Fifty six female pigs were used (Talent × Topigs 20), averaging 75.06±1.68 kg in initial weight, allotted in a completely randomized block design arranged in a 2 × 4 factorial scheme, composed of two vitamin B6 supplementation levels (1.58 and 3.58 mg/kg) and four levels of SID Met+Cys (0.370, 0.470, 0.570, and 0.670%), with seven replicates and one animal per experimental unit. No interactions between vitamin B6 supplementation and SID Met+Cys levels were observed. The levels of SID Met+Cys and vitamin B6 supplementation did not affect animal performance. Triacylglycerols showed a quadratic response to the SID Met+Cys levels, in which the lowest plasma concentration was estimated as 0.575%. Treatments did not affect the expression of the methionine synthase and cystathionine-γ-lyase enzymes or serum homocysteine levels. The SID Met+Cys requirement for female pigs from 75 to 100 kg is equal to or lower than 10.60 g/day, which corresponds to the level of 0.370% Met+Cys in the diet and a relationship 0.48% with the SID lysine.

RESUMO A predição dos valores de energia metabolizável (EM) da farinha de carne e ossos (FCO) para suínos é uma ferramenta interessante, mas os modelos usados para predizer esses valores devem ser validados para garantir maior precisão. Objetivou-se com este trabalho, determinar a composição química e energética de diferentes FCO para suínos; ajustar e validar modelos de predição da EM, a partir da composição química, e validar os modelos, utilizando um conjunto de dados independentes. Foram utilizados 32 suínos machos e castrados, com peso médio inicial de 26,75 ± 1,45 kg, distribuídos individualmente em delineamento experimental de blocos ao acaso, com oito tratamentos e quatro repetições. Os tratamentos consistiram em sete diferentes FCO que substituíram em 20% a ração referência. Para o ajuste das equações de predição, foi utilizado o procedimento estatístico Stepwise, em que a EM foi a variável dependente. Os valores de EM das FCO variaram de 1645 a 2645 kcal kg-1. As equações que, eficientemente, estimaram a EM da FCO, em condições brasileiras, foram: EM1 = -4233,58 + 0,4134EB + 72PB + 89,62MM - 159,06Ca; EM2 = 2087,49 + 0,3446EB + 31,82MM - 189,18Ca; EM3 = 2140,13 + 0,3845EB - 112,33Ca; EM4 = -346,58 + 0,656EB; e EM5 = 3221,27 + 178,96EE - 76,55MM e EM6 = 5356,45 - 84,75MM.

ABSTRACT The prediction of metabolizable energy (ME) of meat and bone meal (MBM) for pigs is an interesting tool, however, used models to predict these values must be validated in order to garantee higher precision. The aim of this study was to determine the chemical and energetic composition of different types of MBM for pigs and to adjust and validate models to better predict the ME based on the chemical composition. Thirty-two barrows, averaging an initial weight of 26.75 ± 1.45 kg, were individually allotted in a randomized block design with eight treatments and four replicates. The treatments consisted of seven types of MBM that replaced 20% of the basal diet. A stepwise procedure was the statistical procedure used to adjust the prediction equations and the ME was the dependent parameter. The validation of the adjusted models was performed using an independent databank of chemical and energetic composition of theBrazilian and international MBM. The metabolizable energy of different meat and bone meals ranged from 1645 to 2645 kcal kg-1. The equations that provide a good prediction of metabolizable energy of meat and bone meal for swine in Brazil are EM1 = -4233.58 + 0.4134GE + 72CP + 89.62ash - 159.06Ca; EM2 = 2087.49 + 0.3446GE + 31.82ash - 189.18Ca; EM3 = 2140.13 + 0.3845GE - 112.33Ca; EM4 = -346.58 + 0.656GE; EM5 = 3221.27 + 178.96fat - 76.55ash; and EM6 = 5356.45 - 84.75ash.

The objective of this trial was to evaluate the bioavailability of DL-2-hydroxy-4-(methyl) butanoic acid (DL-HMBA) and a polyherbal ingredient (PHI) in relation to DL-methionine (DLM) on broilers. Nine hundred male broiler chickens of the Cobb 500 strain were fed from 22 to 42 days of age either a basal diet without industrial methionine supplementation or the basal diet supplemented with DL-HMBA at one of three levels (0.143, 0.286 and 0.429%) or DLM at one of three levels (0.093, 0.186 and 0.279%, each of which is 65% of the respective DL-HMBA level by weight) or PHI at one of the same three levels used for DLM (0.093, 0.186 and 0.279%). The weight gain, feed conversion ratio and relative weights of breast and abdominal fat were improved over that of basal diet-fed broilers by the addition of DL-HMBA and DLM to the diet. A simultaneous exponential regression analysis revealed that the relative bioavailability values for DL-HMBA and PHI were 52% and 5% of that of DLM, respectively, for weight gain, and 57% and 4%, respectively, for feed conversion ratio. Concerning breast meat yield, a simultaneous linear regression analysis (slope ratio) showed that the relative bioavailability for DL-HMBA was 65% of that of DLM. Considering all studied parameters together, the relative bioavailability values for DL-HMBA and PHI are 58% and 4.5% of that of DLM on a product basis.