Antimicrobial effect of bothropstoxin-i in broilers

Bacterial resistance is a sanitary issue explained by indiscriminate use of nonprescription drugs, and antimicrobial use in food production for growth promotion. Bothropstoxin-I (BthTx-I) is a phospholipase A2 (PLA2) from Bothrops jararacussu venom, which has a known antimicrobial effect. The goal of this study was the unprecedented evaluation of in vivo antimicrobial activity of BthTx-I in broilers. Microbiological, biochemical, and histological parameters were determined using 84 21-day old broilers that were kept in cages with four birds each at a density of 625 cm2/broiler. The experiment was randomized by three treatments with seven repetitions of four broilers each that lasted seven days. The treatments were: 1) bacitracin zinc diet; 2) PLA2-BthTx-I; 3) without additives. The data obtained from the studied variables was subjected to analysis of variance and an F-test at the 5% significance level. Averages of each variable in each treatment were compared by Tukey’s test. Broiler bacterial cloacal counts showed that BthTx-I decreased the microbial population without reducing body weight, intestinal morphology, or liver or kidney histopathological damage. The toxin showed in vivo activity, being an alternative for better performance in the production of broiler chickens, because it acted by decreasing the microbial load of potentially pathogenic bacteria in the intestinal microbiota of the birds and did not cause muscle, liver or kidney damage at the assessed dosage.

Effect of cyclic heat stress on thyroidal hormones, thyroid histology, and performance of two broiler strains.

This study determined thyroid hormone (T3 and T4) serum levels and investigated thyroid gland histology, as well as two broiler strains performance kept at different periods of heat stress. Broilers (560 Cobb Slow™ and 560 Hubbard Flex™) were distributed in control environment (0) reared following the thermal recommendations, and environments 1, 2, and 3 exposed to high temperatures for 1 h, 2 h, and 3 h a day, respectively, from 14 to 42 days old. At 21, 28, 35, and 42 days old, blood samples were collected to determine T3 and T4 serum levels. At 42 days old, thyroid glands were removed for histological analyses. The performance was calculated weekly. T3 levels decreased with age advance, while T4 serum concentration was higher at 42 days old (23.27 nmol L-1) and lower at 28 days old (15.69 nmol L-1). The histological sections revealed that thyroid morphology was well preserved. Live weight was higher in Cobb Slow™ (2.97 kg) than Hubbard Flex™ (2.93 kg) broilers at 42 days old. It is possible to conclude that cyclic heat stress exposure for a 3-h period from 14 to 42 days old did not affect performance, thyroid histology, or T3 and T4 serum levels. Cobb Slow™ broilers had the best live weight values at slaughtering. With increasing age, T3 levels decreased and T4 levels increased for both strains.

Millet and corn oil in sorghum-based diets for broilers / Milheto e óleo de milho em dietas a base de sorgo para frangos de corte

ABSTRACT:This study evaluated the effects of millet and corn oil additions to sorghum-based diets on the performance, carcass yields and prime cuts (i.e., wings, breasts, thighs and drumsticks) and the relative weights of edible offal (i.e., gizzard, heart, and liver) of broiler chickens. A total of 684 Hubbard Flex chickens, including 342 broilers of each sex, were housed. The design was completely randomized, and the following diets were supplied: A) sorghum and soybean meal + soybean oil (control); B) sorghum and soybean meal + corn oil; and C) sorghum and soybean meal + millet and soybean oil. Six replicates with 38 birds each (19 males and 19 females) were evaluated regarding each experimental diet. At 14, 21, 35 and 42 days of age, the feed intake, weight gain, feed conversion and viability of the chickens were evaluated. At 42 days, the live weight, carcass yield, prime cuts and relative weight of the edible offal were measured. The dietary inclusion of either millet or corn oil did not affect any of the parameters. In conclusion, additions of millet and corn oil to sorghum-based diets of broilers do not compromise poultry performance.

RESUMO:Objetivou-se avaliar os efeitos da inclusão de milheto e óleo de milho em dietas a base de sorgo sobre o desempenho, rendimento de carcaça e de cortes nobres (asas, peito, coxa e sobrecoxa) e peso relativo das vísceras comestíveis (moela, coração e fígado) de frangos de corte. Foram alojadas 684 aves, sendo 342 de cada sexo, da linhagem Hubbard Flex. O delineamento foi inteiramente casualisado, composto pelas dietas: A) sorgo+farelo de soja/óleo de soja (controle), B) sorgo+farelo de soja/óleo de milho e C) sorgo+farelo de soja/milheto+óleo de soja. Cada dieta experimental foi avaliada em seis repetições de 38 aves cada (19 machos e 19 fêmeas). Aos 14, 21, 35 e 42 dias de idade das aves, avaliou-se o consumo de ração, ganho de peso, conversão alimentar e viabilidade. Aos 42 dias, foi obtido o peso vivo, rendimento de carcaça e de cortes nobres, além do peso relativo das vísceras comestíveis. A inclusão de milheto ou óleo de milho nas dietas não alterou nenhum dos parâmetros avaliados. Concluiu-se que, em dietas a base de sorgo para frangos de corte, o milheto e o óleo de milho podem ser adicionados sem comprometer a produtividade das aves.