s.n. mosavi

Researches on the effects of dietary Arginine (Arg) and Guanidioacetic acid (GAA) indicated that requirements for Arg in poultry diets vary significantly depending on feed composition, disease challenges and environmental conditions (Khajali and Wideman. 2010). Reproductive performance and fertility of broiler breeder flock are decreased sharply with ageing (Zaghari et al. 2013). It is suggested that the age-related decrease in fertility is more pronounced in females, in which the efficiency of sperm storage tubules decreases (Gomulka and Kapkowska. 2005). Silva et al. (2012) reported that dietary inclusion of Arg improved egg weight and egg production in broiler breeder hens. It has been reported that GAA supplementation improved hatchability and total fertility of eggs (Murakami et al. 2014). GAA may be beneficial in poultry diets because it may be able to spare Arg; this is an important point considering Arg is the fifth limiting AA in corn-soybean diets for poultry (Dilger et al 2013). This study was conducted to evaluate arginine requirement of broiler breeder hens in practical diet and investigating of the spare effect of GAA for Arg, as well.
Material and A total of 320 Ross 308 broiler breeder hens in a factorial arrangements were assigned to eight treatments (two concentrations of GAA (0 and 0.12%) × four concentrations of L-Arginine (0, 0.3, 0.6, and 0.9%)) with four replicates during 54 to 63 wk. of age. The hens received a practical diet containing 2800 kcal ME/kg and 13%CP. Basal diets were formulated to be singly deficient in Arg (73%). From 54 to 63 weeks of age. The number of produced eggs was recorded daily. At the end of experiment, the following parameters were studied: feed clean up time, feather score, IgG and antibodies against SRBC as immune responses. When the hens were 62 weeks old, the time taken by the hens to consume all the feed was measured. At 63 weeks old, feather coverage of the back of each hen was scored on a scale of 1 to 5, following modification to the system reported by Sikur et al. (2004). At 61 week of age, 2 birds, from each treatment group, were injected, intramuscularly, with 0.2 mL of 5% SRBC suspension prepared in 0.9% physiological saline. One week following the injection, the antibody production against SRBC was measured using microhemagglutination technique. Blood samples were collected from each treatment group. Antibody values were expressed as log2 of the reciprocal dilution where the last agglutination was observed (Gharib et al, 2008). To evaluate the fertility, the hens were inseminated with 250µl [100 × 106 sperm/hen; diluted in a modified Beltsville extender without lecithin and glycerol] of the pooled semen at 61 and 62 weeks of age. The eggs were collected during 2 through 8 day following each insemination. The eggs were incubated for further analysis of fertility. Sperm penetration holes in the inner perivitelline layer overlying the germinal disc were enumerated on days 3 and 7 following each insemination (Sharide et al. 2015) as fertility. Arg requirement was determined by using broken line model, linear and non-linear regressions according to performance and dietary Arg concentration.
Effects of added Arg and GAA on the total hen housed egg production, hen housed hatching egg production and feather coverage was not significant (P 0.05) on IgG production, although the regression of IgG was quadratic (P The results of this study revealed that, recommendation of Ross 308 management guide for Arg requirement is underestimated. This work suggested that GAA could increase performance of birds fed Arg-adequate corn-soybean meal diets. GAA spared part of Arg function for fertility.