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No abstract

RESUMO O objetivo foi avaliar o efeito do uso de extrato de plantas sobre a resposta imune, o desempenho produtivo e a morfometria intestinal de frangos de corte desafiados com a vacina contra coccidiose. Foram utilizados 720 pintos de corte, machos, distribuídos em um delineamento inteiramente casualizado com quatro tratamentos e nove repetições de 20 aves cada. A partir dos 14 dias, as aves passaram a receber os tratamentos experimentais compostos por A – Dieta basal + Antibiótico promotor do crescimento (APC) ; B - Dieta basal + APC + desafio vacinal; C - Dieta basal + extrato de plantas, e D - Dieta basal + extrato de plantas + desafio vacinal. As aves dos tratamentos B e D receberam vacina oral contra coccidiose (vinte vezes a dose individual recomendada pelo fabricante). A adição de extrato de plantas à dieta de aves desafiadas com oocistos de Eimeria sp aumentou (p <0,05) a secreção de IgA pela mucosa intestinal. As lesões microscópicas da mucosa intestinal não foram influenciadas (p >0,05) pelo desafio ou pelo uso do extrato de plantas. O desafio com oocistos de Eimeria sp ou associado ao extrato de plantas resultou em menor (p <0,05) ganho de peso e pior conversão alimentar apenas na semana seguinte à inoculação. Os resultados obtidos mostraram que a adição de extrato de plantas à dieta de aves submetidas ao desafio vacinal aumentou a secreção de IgA pela mucosa intestinal e que a inclusão do extrato de plantas ou de melhorador de desempenho resultou em desempenho produtivo semelhante.

Differences in growth rate and carcass composition of broilers may require higher levels of vitamins and minerals with higher bioavailability. The aim of this trial was to supplement commercial diets for broilers with optimized levels of vitamins and with different mineral sources to assess the effect on performance, carcass yield and bone quality. A total of 1,800 Cobb Slow male broiler chicks were distributed into a 2 x 2 factorial completely randomized design (vitamin programs - optimized and commercial versus mineral sources - inorganic [sulfates] and carbo-amino-phospho-chelate, CAPC). The vitamin D3 metabolite, 25 (OH) D3, was included in the optimized vitamin premix. Birds and feed leftovers were weekly weighed. Data was subjected to statistical analysis using the GLM procedure of SAS software. Supplementing diets with a combination of optimized vitamin programs and CAPC as mineral source resulted in better feed conversion at 42 days of age (P<0.05). Supplementation with CAPC minerals resulted in a lower red index (*a) (P<0.05) in the adjacent thigh muscles and drumstick bones of broilers when thawed and roasted, indicating less bone porosity. The inclusion rates of mineral sources with higher bioavailability can be reduced, decreasing the negative impact of mineral excretion and the polluting effect on the environment.

The aim of this study was to evaluate the effects of glutamine and threonine supplementation on the ileal mucosa of broilers aged 21-42 days. Six-hundred and forty-one-day old chicks of the Cobb Slow lineage were utilized in this study. From 1 to 21 days of age, the chicks received a commercial diet; and after 22 days, the broilers were distributed in a completely randomized design in a 2 ? 4 factorial scheme (challenge and diet), with 4 replications and 20 chicks per experimental unit. At 22 days of age, the challenged broilers received a commercial vaccine against coccidiosis. A commercial diet was utilized as control and three other diets were formulated with reduced crude protein (-3%), and were corrected with the addition of glutamine (Gln) and glutamic acid (Glu) as non-specific nitrogen sources, and finally supplemented with L-Threonine (Thr) at 0.70, 0.80, and 0.85% digestible threonine, respectively. At 28 days of age, diets with Gln/Glu + Thr resulted in greater ileal villi lengths. Challenge with Eimeria sp. reduced the number of goblet cells and increased the duodenal and jejunal crypt depths. At 42 days of age, an interaction was observed between diet and challenge in relation to ileal villi length; better results were observed in the challenged broilers that received 0.85% Gln/Glu + Thr. The mucosal morphology in the ileal villi extremities was preserved in the challenged broilers that received higher Thr levels in their diets. The results suggested that the inclusion of glutamine and threonine affected the morphometry and mucosa of the ileum, thereby improving the mucosal quality.