Effects of Reduced- Protein Diets at Constant Total Sulfur Amino Acids: Lysine Ratio on Pullet Development and Subsequent Laying Hen Performance

Abstract

Abstract:The effect of using a low protein regime in pullet development and subsequent layer performance was studied. The experiment consisted of two periods of rearing and laying. Two hundred and sixty Hy-line W36 chicks were used. In the rearing period, dietary protein level and ME content series of the control group used during starter (18-42), grower (43-63) and developer (64-119d) phases were 20, 2930, 18, 2930, and 16, 3025, respectively. Dietary protein sequence of the low protein group was 18.5, 16.5, and 14.6% during the respective periods. In the laying period lasted from week18 to week32 of age, CP content of the control and reduced-protein diets were 17.8 and 16.3%, respectively. Reduced-protein diets were kept isoenergetic with their corresponding controls in each period and phase and they balanced to keep the same total sulfur amino acid to lysine ratio as well. Results indicated that birds on reduced-protein diet during starter phase of the rearing period consumed less feed (p = 0.003) and as a result they had significantly (p = 0.012) better feed conversion ratio (FCR) compared to the control. However, dietary protein regime had no significant effect on weight gain, feed intake and FCR during grower and developer phases. In the laying period, there was no significant difference in terms of layer performance and egg quality criteria. In conclusion, reduced-CP diets can be satisfactory used for rearing pullets and laying hens up to 32 weeks of age.

<b>Digestible lysine levels for laying hens and their effects on egg quality</b>

“…The results are similar to those by Khajali et al (2007), or rather, the maintenance of the digestible amino acid / digestible lysine ratio allowed the reduction of protein levels of the diets of laying hens without impairing the levels of internal egg quality. In their studies on laying hens aged between 34 and 50 weeks, Sá et al (2007) failed to report any effect of the variation in digestible lysine levels on the Haugh unit parameter.…”

“…Due to rise in production costs in animal nutrition caused by considerable increase in the prices of the main inputs, several studies have been undertaken on alternatives that might reduce crude protein levels for better economic results (KHAJALI et al, 2007) and lower environmental impact of the polluting excreta, mainly nitrogen (ROCHA et al, 2009) and ammonia emission rates (ROBERTS et al, 2007). Dudle-Cash (2012) inferred that, in normal conditions, diets for breeding broilers contained up to 40% excess levels of digestible lysine.…”

Effect of dietary concentrations of energy, crude protein, lysine, and methionine on the performance of White Leghorn layers in the tropics

“…1 Data are means from 8 replicates of 88 birds in each replicate. [2,15] have also suggested 16 to 16.3% CP for layers during the initial laying phase (up to 32 wk of age) to sustain a performance similar to that of layers fed 17.8 to 18% CP. The higher levels of CP required during the initial laying period may be due to a constant increase in the rate of EP to reach peak lay with a simultaneous gain in BW.…”

“…A large part of the differences in nutrient requirements may be attributed to differences in environmental temperature [13], strain [14], and age of the birds. Most requirement studies with layers have been conducted during the early [15,16], middle [6], or late production [17] phases. Experiments conducted for a short duration or for part of the egg production (EP) cycle may not truly represent the entire production cycle.…”

Effects of Different Levels of Dietary Crude Protein on Egg Production and Quality in Laying Hens during Early Stage of Egg Production

“…이와는 다르게 Roberts et al (2007) (Karunajeewa, 1972;Masahiro et al, 1999;Morihiro et al, 2001), 많은 연구에서 xanthophyll 함량이 높을수 록 난황 내 더욱 많은 색소들이 침착되어 짙은 색을 보인다 고 하였다 (Karunajeewa, 1972;Liu et al, 2004;Prochaska et al, 1996). 또한, 옥수수는 대체로 20∼25 mg의 xanthophyll 을 함유하고 있으며 (Sikder et al, 1998) (Khajali et al, 2007;Novak et al, 2006;신 등, 1989). 그러 나 난각 두께 및 강도를 제외한 전반적인 난각 품질에 있어 서 조단백질 수준이 낮을수록 품질이 떨어진다는 보고도 있 으며, 이것은 사료 내 TSAA : Lys 비율 차이에 기인한 것이 라 하였다 (Keshavarz and Nakajima, 1995;Keshavarz and Jackson, 1992;Leeson and Caston, 1997 …”