Potential alternative feed sources for ruminant feeding from the biodiesel production chain by-products

This study aimed to evaluate the chemical composition, fractionation of nitrogen compounds and carbohydrates, digestibility parameters, gas production kinetics and ruminal fermentation of fruit seed cakes. The experiment was conducted in a completely randomized design with three fruit seed cakes (treatments) and four replications. The cakes were made of seeds of custard apple (Annona squamosa), soursop (Annona muricata) and passion fruit (Passiflora edulis), which were collected in a biodiesel plant. The passion fruit seed cake presented the highest content of dry matter, neutral detergent fibre crude protein (NDFcp), acid detergent fibre (ADF), lignin and total carbohydrates (P<0.05). The custard apple seed cake presented high proportions of crude protein, condensed tannins and digestible energy (P<0.05). The soursop seed cake presented higher values for ether extract and total digestible nutrients (P<0.05). For potential degradability, the authors detected a difference between the custard apple, soursop and passion fruit seed cakes. The total volume of gases was higher for custard apple and soursop seed cakes. Custard apple seed cake presented higher proportions of in vitro degradation parameters (P<0.05). Thus this cake could provide greater nutrient levels when supplied in ruminant diets, followed by soursop seed cake and passion fruit seed cake. Keywords: alternative food, by-products, ruminant feeding, seed cake, semi-ari

Body composition and net protein and energy requirements for weight gain of crossbred dairy cattle in grazing Composição corporal e exigências líquidas de proteína e energia para ganho de peso de bovinos mestiços leiteiros em pastejo

The body composition and net protein and energy requirements for weight gain of 5/8 Hostein-Zebu crossbred cattle raised in Brachiaria decumbens Spaft pasture were evaluated. In total, 16 bulls with 10 months of age and body weight (BW) of 180 ± 19.95 kg were used. The animals were kept with free access to pasture or with restricted grazing (from 6 to 10 h). Four animals were slaughtered at the beginning of the experimental period to estimate the empty body weight (EBW) and the initial body composition of the remaining animals. The other animals were slaughtered at the end of the 84-day trial period. The logarithm equations of the protein and energy body content were adjusted according to the logarithm of the empty body weight EBW. From these equations, the net protein and energy requirements for weight gain were estimated. There was an increase in fat (from 37.17 to 59.08 g/kg EBW) and energy (from 1.68 to 1.94 Mcal/kg EBW) concentrations, with increase in body weight from 150 to 250 kg. The protein and energy requirements for gaining 1 kg of EBW increased with the increase in body weight or empty body weight. The relationship between fat concentration in gain and protein requirements also increased, indicating that as the BW or EBW increase, more fat deposition in the gain is observed.<br>Avaliaram-se a composição corporal e as exigências líquidas de proteína e energia para ganho de peso de bovinos mestiços 5/8 Holandês-Zebu criados em pasto de Brachiaria decumbens Spaft. Utilizaram-se 16 bovinos machos, não-castrados com 10 meses de idade e peso vivo de 180 ± 19,95 kg. Os animais foram mantidos com livre acesso ao pasto ou com pastejo restrito (das 6 às 10 h). Quatro animais foram abatidos no início do experimento para estimativa do peso do corpo vazio (PCVZ) e da composição corporal inicial dos animais remanescentes. Os demais foram abatidos ao final do período experimental, de 84 dias. Ajustaram-se as equações do logaritmo dos conteúdos corporais de proteína e energia em função do logaritmo do peso de corpo vazio PCVZ. Derivando-se essas equações, estimaram-se as exigências líquidas de proteína e energia para ganho de peso. Com a elevação do peso vivo de 150 para 250 kg, houve aumento nas concentrações de gordura (37,17 para 59,08 g/kg PCVZ) e energia (1,68 para 1,94 Mcal/kg PCVZ). As exigências de proteína e energia para ganho de 1 kg de PCVZ elevaram com o aumento do peso vivo ou do peso de corpo vazio. As relações entre as concentrações de gordura no ganho e as exigências de proteína também foram crescentes, evidenciando que, à medida que o peso vivo ou peso do corpo vazio aumentam, ocorre maior deposição de gordura no ganho