Methods of feed restriction for molt induction in commercial laying hens

Abstract

An experiment was carried out to evaluate methods of quantitative or qualitative feed restriction for inducing molt on the performance of Hy -Line Brown layers in the second lay cycle. Two hundred and twenty -five birds with 88 wks-old Hy -Line Brown were used in a completely randomized design with five treatments: Quant 100 -restriction of 100% of the daily amount recommended by lineage manual; Quant 75 -restriction of 75% of the daily amount recommended; Quant 50 -restriction of 50% of the daily amount recommended; Qual 75 -supply of an ad libitum diet with 75% grinded rice hulls and 25% of basal diet; Qual 50 -supply of an ad libitum diet with 50% of grinded rice hulls and 50% of basal diet. The feed conversion ratio per dozen eggs and egg mass was similar (P=0.0035 and P=0.0139) between Quant 75 and Qual 75 methods, in relation to Quant 100 . The eggs production was similar (P=0.0122) among the hens from Quant 75 , Quant 50 and Qual 75 methods, in relation to Quant 100 . The methods of feed restriction did not alter the eggs density (P=0.8971). Quant 75 or Qual 75 methods can substitute the conventional method for inducing molt in Hy-Line Brown layers, without modifying the performance in the second lay cycle. Key words: Brow egg, commercial laying, Gallus gallus, molt, performance ResumoO objetivo do trabalho foi avaliar métodos de restrição alimentar quantitativa ou qualitativa para a indução a muda sobre o desempenho de poedeiras Hy-Line Brown no segundo ciclo de produção. Foram utilizadas 225 aves com 88 semanas de idade em um delineamento inteiramente casualizado com cinco tratamentos: Quant 100 -restrição de 100% da quantidade diária de ração recomendada para a linhagem; Quant 75 -restrição de 75% da quantidade diária de ração recomendada; Quant 50 -restrição de 50% da quantidade diária de ração recomendada; Qual 75 -dieta com 75% de casca de arroz e 25% de dieta basal; Qual 50 -dieta com 50% casca de arroz e 50% de dieta basal. A conversão alimentar por dúzia e por massa de ovos foi similar (P=0,0035 e P=0,0139) para os métodos Quant 75 e Qual 75 em relação ao Quant 100 . A produção de ovos foi semelhante (P=0,0122) para as poedeiras dos tratamentos Quant 75 , Quant 50 e Qual 75 em relação ao Quant 100 . Os métodos de restrição alimentar não alteraram (P=0,8971) a densidade dos ovos no segundo ciclo. Os métodos Quant 75 ou Qual 75 podem substituir o método tradicional (Quant 100 ) para induzir a muda em poedeiras Hy-Line Brown, sem alterações no desempenho das aves no segundo ciclo de produção. Palavras-chave: Desempenho, Gallus gallus, ovo marrom, postura comercial, troca de penas

Methods for identifying stress caused by fasting in commercial laying hens

“…The birds weighed 2.072 g ± 137 g at the beginning and 1.501 g ± 126 g at the end of the fasting period, resulting in a mean weight reduction of 27.7%. This reduction indicated that the fasting to which the birds were subjected was successful, as recommended by CERBARO et al (2014).…”

“…During fasting, egg production is temporarily interrupted, allowing the reproductive system to rest and the bird to prepare for a new cycle of egg production (LEE, 1982). This procedure is considered highly stressful (HOSHINO et al, 1988;KOELKEBECK & ANDERSON, 2007), and some alternative protocols have been tested, to maintain the welfare of the birds by reducing the stress (BOZKURT et al, 2016;CERBARO et al, 2014;GONGRUTTANANUN et al, 2013). However, no studies have jointly tested the methods applied to evaluate the physiological stress arising from feed restriction in commercial laying hens.…”