پديد آورندگان :
اسمعيلي نيا، ليدا دانشگاه تهران - گروه علوم دامي , زاغري، مجتبي دانشگاه تهران - گروه علوم دامي , موسوي، ناصر دانشگاه آزاد اسلامي واحد ورامين پيشوا - گروه علوم دامي
چكيده لاتين :
Introduction: 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 methods: 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. Results and discussion: 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) (Table 2). Although the most hen housed total egg production was resulted in 0.3% added Arg supplemented with GAA and addition of Arg increased frequency of birds with full back feather coverage (feather score of 5). Feed clean up time was significantly become longer about two times, in 0.6% and 0.9% of added Arg. The results showed that the interaction of Arg and GAA was significant on fertility (Sharide et al. 2015). GAA may be important for poultry nutrition not only as a replacement for dietary Arg, an essential nutrient, but also to support overall energy homeostasis of the bird (Dilger et al. 2013).The efficacy of GAA as a creatine precursor has been shown in broilers (Michiels et al. 2012), It has been reported that GAA was successfully absorbed by gastrointestinal tract of avian and there is a carry-over on the fluid of the reproductive tract; supplementation with GAA may be important to provide additional levels of creatine in the female reproductive tract, enabling the maintenance of the viability of a greater number of spermatozoa until they are used to perform fertilization, considering that birds may store spermatozoa after mating for long periods of time in the tubular gland of the uterovaginal junction and that creatine may improve the stability of cellular membranes (Murakami et al. 2014). Increasing dietary level of Arg resulted significant effect on anti SRBC. Dietary Arg levels and GAA did not affect (P > 0.05) on IgG production, although the regression of IgG was quadratic (P < 0.05) according to the increase in dietary Arg levels. The requirement of Arg during immunological responses has been widely studied because Arg is the substrate from which nitric oxide (NO) is generated. Nitric oxide also is a modulator of certain immune functions. It has been reported that Arg levels sufficient to support maximal performance rates are not adequate (Khajali and Wideman. 2010). Arg requirement for egg production, fertility and immunity were determined for breeders; four equations were developed from the feeding experiment to predict Arg needs for breeders in the absence (Table 3) and presence of 0.12% GAA (Table 4). The Broken line and quadratic responses allowed parameters to vary by supplemental Arg and GAA levels. When GAA was added to the Arg-deficient diet, there were improvements in both fertility and immunity (Fig 1). Digestible Arg required for hen housed total egg production, hen housed hatching egg production, sperm penetration and IgG in the absence of GAA, estimated 0.85, 0.87, 1.03 and 1.27%, respectively and in the presence of 0.12% GAA estimated 1.02, 0.91, 1.00 and 1.34%, respectively. Fitted regression of hen housed egg production, which was estimated Arg requirement, is in agreement with other observations of recent work (Silva et al. 2012).
Conclusion: 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.
