Influence of dietary energy, supplemental fat and linoleic acid concentration on performance of laying hens at two ages

Abstract

1. The aim of this study was to investigate the influence of metabolisable energy (ME), supplemental fat (SFAT) and linoleic acid (LIN) content of the diet on the productive performance and weight of eggs and egg components of Isabrown hens of 22 or 74 weeks of age. 2. Six diets were formulated to contain the following concentrations of ME (MJ/kg), SFAT (g/kg) and LIN (g/kg), respectively: A) 11.8, 0 and 11.5; B) 11.8, 40 and 11.5; C) 11.8, 40 and 16.5; D) 11.2, 40 and 16.5; E) 11.2, 40 and 11.5; and F) 11.2, 0 and 11.5. Data were collected for 28 d and analysed using linear contrasts to test the effect of SFAT, LIN, ME and their interactions. 3. When the LIN content of the diets was maintained constant at 11.5 g/kg, an increase in the SFAT from 0 to 40 g/kg increased egg weight (63.8 vs 64.5 g; P<0.05), food intake (119 vs 124 g; P<0.01) and energy intake (1.36 vs. 1.42 MJ/d; P<0.01) and body weight change of the hens (-85 vs. 27 g; P<0.001). Supplemental fat also increased yolk (15.8 vs. 16.3 g; P<0.001) and albumen weight (40.8 vs. 42.3 g; P<0.01) but yolk to albumen ratio was not modified. 4. Egg and albumen weights were improved by SFAT in early but not in late producing hens. As a result, yolk to albumen ratio decreased in the younger hens, from 0.371 to 0.357, but increased in the older hens, from 0.408 to 0.415; P<0.01) with fat addition. 5. An increase in the LIN content of the diets from 11.5 to 16.5 g/kg did not modify any of the traits studied. 6. It was concluded that the LIN requirement of the hens for maximal productivity and weight of eggs is 11.5 g/kg or less. Supplemental fat increased the weight of eggs and albumen in the younger but not in older hens and the beneficial effect was independent of its LIN content.

Exigência nutricional de lisina digestível para galinhas poedeiras de 54 a 70 semanas de idade

“…Resultados semelhantes ou até superiores também foram encontrados por outros autores (Novak & Scheideler, 2004;Sá et al, 2007). Ressalta-se que diversos fatores interferem na resposta produtiva das aves e por consequência nos níveis nutricionais recomendados, como por exemplo, a idade (Grobas et al, 1999), a genética utilizada (Tharrington et al, 1999), a temperatura ambiental (Faria et al, 2001) e as variáveis consideradas na determinação da exigência (Goulart, 1997).…”

Exigência nutricional de metionina+cistina digestíveis para galinhas poedeiras de 54 a 70 semanas de idade

“…Ressalta-se que diversos fatores podem interferir na resposta produtiva das aves e consequentemente nos níveis nutricionais recomendados, por exemplo, a idade (Grobas et al 1999), a genética utilizada (Tharrington et al, 1999), a temperatura ambiental, o método estatístico utilizado nas análises (Jansman & Klis, 2002) e as próprias variáveis consideradas na determinação da exigência (Goulart, 1997).…”

Influence of feed form and energy concentration of the rearing phase diets on productivity, digestive tract development and body measurements of brown-egg laying hens fed diets varying in energy concentration from 17 to 46 wk of age

“…Moreover, when the lipid content of the diet increases, the level of LNA content also increases. Both effects, reduced rate of passage and increased LNA content, might result in an increase in egg size and an improvement in FCR (Grobas et al, 1999c). In the current experiment, the low and high energy diets contained 54 and 68 g/kg ether extract and 19 and 27 g/kg LNA, respectively.…”