High environmental temperature is limiting factor in broiler production. In order to minimize the undesirable consequences of acute or chronic heat stress, the techniques of fixed dietary electrolyte balance and early heat conditioning were evaluated. The objective of this study was to evaluate the possible interactions and effects of dietary electrolyte balance and early heat conditioning on feed intake, body weight, feed conversion ratio, mortality, energy bioeconomic index, fecal moisture, abdominal fat, and breast meat color (L*a*b*) of broilers submitted to chronic or acute heat stress. In total, 1280 chicks, were equally divided in experiment I (chronic heat stress, 6h/day at 32ºC from 35 to 39 d of age) and II (acute heat stress, 36 ºC for 6h at 38 days of age). The data of both experiments were combined and analyzed according to a 2x2x2 factorial arrangement (early heat conditioning (ETC) or not; fixed dietary electrolyte balance (EB) or not; and exposure to acute or chronic heat stress). ETC consisted of exposing 5-d-old birds to 36.0 °C for 24 hours. No interaction among the evaluated factors was detected. Birds exposed to acute heat stress presented significantly higher compared with chronic heat stress. Fixed dietary EB resulted in significantly higher fecal moisture. Lower abdominal fat percentage was obtained in birds exposed to chronic relative to acute heat stress. Higher breast meat L* and b* values were observed in birds exposed to acute heat stress than those submitted to chronic heat stress, indicating worse meat quality.

Eimeriosis represents a considerable challenge faced by the global poultry industry due to the damage it causes. Three species of Eimeria in chickens, in this case, E. acervulina, E.max and E. tenella have the potential to affect the occurrence and extent of resistance to anticoccidial drugs and future vaccines. Thus, it is clear that vaccination against avian eimeriosis has an important role in maintaining biosafety and productivity in poultry breeding, since in addition to providing the immunization of animals, it helps in increasing the therapeutic efficiency of anticoccidial drugs. In this study, we investigated the effectiveness of vaccination against eimeriosis in broiler birds. In total, 589 articles were compiled in research databases and scientific publications. As a filter to avoid duplication between works, 62 articles were obtained. Of these, in only five did we observe a very high degree of recommendation for the use of DNA vaccination, which was considered more effective in preventing eimeriosis, with a lower degree of side effects.

No abstract

Descrever o crescimento não é tarefa fácil, os processos bioquímicos demandam tempo, pois em sua dinâmica ocorrem mudanças de tamanho, formato e proporções. Pode-se considerar que esse processo, apresenta quatro fases: crescimento exponencial; linear; decrescente; peso estabilizado (adulto). Para justificar os diferentes comportamentos da curva, considera-se limitações nos recursos como: disponibilidade de nutrientes, oxigênio, espaço, exigências de manutenção, inviabilizando que o crescimento se mantenha apenas na primeira fase exponencial (Lawrence e Fowler, 2012; Garcia-Neto, 2018). Os dados foram tabelados no Excel 2010, transferidos para a Programa Prático de Modelagem (PPM) e ajustados pelo modelo matemático de Richards: y = a [1+(b-1) e-c(x-d)]1/(1-b), sendo o input a idade do animal em dias e o output, o peso em kg.Cassiano et al., 2018, descreve que o programa proporciona um conceito fundamental para o estudo do crescimento animal ou qualquer sistema biológico.A idade do animal não nos permite encontrar os pontos F1, Fi e F2 e F3 na curva, porém nota-se que a curva tende a continuar crescente se as condições seguirem favoráveis para tal. Mostra também a aplicabilidade do programa para animais silvestres, tornando possível acompanhar o desenvolvimento do animal, visto que pesquisas com dietas e crescimento de animais silvestres em cativeiro ainda são excassas na literatura.