Effect of variable levels of digestible valine on growth performance, carcass characteristics and serum biochemical profile in commercial broilers

Introduction

In order to meet the growing demand for poultry products, global poultry production has grown significantly over the past 50 years. Feed alone accounts for around 70% of the total cost of broiler production. Growing concerns with regard to the environmental impact of livestock farming such as nitrogen and phosphorus contamination as criteria in feed formulation, feeding optimum and balanced nutrients play an important role in precision nutrition. Corn and soybean meal (SBM) contribute to the majority of broiler chicken diets. Such diets' amino acid (AA) concentrations are insufficient to satisfy the needs of today's rapidly growing broilers in order for them to maximize their full genetic potential. In diets based on soybean and corn meal, valine is fourth limiting AA. If broiler diets lack this AA, growth performance would be hampered. The emphasis currently is on meeting the requirements of this AA in broiler diet as feed-grade valine became commercially available. In diets lacking animal protein ingredients, Val can be next-limiting to threonine. Its primary biological role is to aid in muscle protein synthesis, or growth performance. Val is also a limiting amino acid in broilers, and a minimum digestible Val to lysine ratio of 80% is recommended. As feed grade L-Val is now available, the feed industry has an opportunity to further lower the quantity of protein in the diet. Goals related to nutrition, economy, and the environment, such as increasing feed efficiency, lowering the quantities of protein that birds consume, which improves health and lowers digestive disorders, lowering feed costs, and lowering nitrogen excretion from birds into the environment, can all encourage use of feed grade L-Val.

Materials and Methods

A 6weeks growth trial with 5 dietary treatments was carried out "in commercial broilers using 250 day "old male broiler chicks (Ven Cobb-400)" in CRD (completely randomized design). After obtaining the chicks, their wings were banded and weighed for uniform body weight. Later, they have been randomly separated into 5 treatments, individually of which comprised 10 replicates and total 5 chicks in each replicate.

Chicks have been kept in battery brooders which have been heated electrically to provide the perfect brooding atmosphere. [4] who described an rise in body weight gain by 0.90% and 0.84% dietary Val supplementation during 1-21d and 21-35 d in Cobb broilers.

Experimental diets

Feed intake

Cumulative feed intake (0 to 42 days) revealed feed intake demonstrated significant (p<0.05) elevation in feed intake due to inclusion of digestible Val as 0.826, 0.735 0.665% (70% of digestible lysine) through" pre-starter, starter, finisher phases" correspondingly, in broilers fed diets on based of corn and soybean meal. Lowest cumulative feed intake was observed in broilers fed digestible Val at 0.708, 0.630, 0.570% (60% of digestible lysine) through "prestarter, starter, finisher phases" correspondingly. This is as per findings of Rodehutscord et al. (2005) [8] . Some studies suggested that the dietary Val supplementation have significantly (P less than 0.05) elevated feed consumption in commercial broilers (Corzo et al., 2007) [2] .

Feed conversion ratio (FCR)

The cumulative (0-42 d) FCR displayed significantly increased FCR in group fed digestible Val at 0.708, 0.630, 0.570% (60% of digestible lysine) through "prestarter, starter, finisher phases" correspondingly in broilers. Nevertheless, FCR has been significantly (p<0.05) higher in groups fed digestible Val at 60% of the digestible lysine than other groups fed graded concentration of digestible valine in broilers during overall experimental period. This is in concurrence with outcomes of Corzo et al. (2004) [2] along with Rodehutscord et al. (2005) [8] . These studies suggested that the 0.45% and 0.67% dietary Val supplementation significantly (p<0.05) elevated FCR in commercial broilers.

Carcass parameters

Supplementation of graded concentration of digestible Val did not influence the dressing percentage in broiler diets. These observations are in support with outcomes of Ospina-Rojas et al. (2014) [7] . It is detected that supplementation of the digestible valine had no significant (p<0.05) influence on dressing%. Breast weight has been significantly (p<0.05) impacted by changes in concentration of digestible Val in broiler diets. But lower breast weight has been observed in group fed digestible Val at 60 percent of digestible lysine, in contrast to additional concentration of valine in the diet. These observations are in support with the findings of Ospina-Rojas et al. (2014) [7] . Possibly, Val levels showed greater influence on the diameter of the red muscle fiber (Potenca et al., 2015). AFW has been significantly (p<0.05) impacted by changes in concentration of Val in broiler diets. Lower AFW has been determined at 100% Val concentration in broiler diet opposed to other Val concentration. However, AFW has been detected more in group (T 5 ) fed digestible Val at 60 percent of digestible lysine in broiler diets. These findings are in accordance with those of Ospina-Rojas et al. (2014) [7] . Contrary to the findings recorded in this study, Leitged et al. (2004) have observed no effect on slaughter performance due to dietary Val supplementation.

Serum biochemical parameters

Supplementation of digestible Val in broilers diets had no significant influence on serum biochemical constituents viz., glucose, total cholesterol, uric acid, triglycerides, LDL (low density lipoprotein) as well as HDL (high density lipoprotein) cholesterol or VLDL cholesterol among treatment groups in the present study. Such outcomes are in similar as of Ospina-Rojas et al. (2014) [7] .

Conclusion

According to results of ongoing biological research, this is decided digestible Val concentrations during pre-starter, starter and finisher phases at 70% of the digestible lysine (0.826, 0.735 and 0.665% respectively) are optimum for getting good economic returns without having negative impact on growth performance, slaughter parameters and serum biochemical parameters in current fast growing commercial broilers.

Acknowledgement

AcknowledgementsAuthors are thankful to M/s Evonik (SEA) Pvt. Ltd. Singapore for providing financial assistance to conduct the present experiment on commercial broilers.

References

1. Corzo A, Kidd MT, Dozier WA III, Vieira SL. Marginality and needs of dietary valine for broilers fed certain all-vegetable diets. Journal of Applied Poultry Research. 2007;16:546-554.
2. Corzo A, Moran ET Jr, Hohler D. Valine needs of male broilers from 42 to 56 days of age. Poultry Science. 2004;83:946-951.
3. Duncan DB. New multiple range and 'F' test. Biometrics. 1955;11:1-42.
4. Goodgame S, Coto C, Mussini F, Lu C, Karimi A, Yuan J, Waldroup P. The potential role of valine in commercial poultry diets. International Poultry Scientific Forum. 2011;Abstract 217:30.
5. Leitgeb R, Tschischej M, Hutter E, Bartelt J. Impact of protein reduction and arginine and valine supplementation in the diet on growth and slaughter performance of broilers. Bodenkultur. 2004;54:187195.
6. Ospina-Rojas IC, Murakami AE, Eyng C, Picoli KP, Scapinello C, Duarte CRA. Threonine-lysine ratio on the requirements of digestible lysine in diets for broilers. Acta Scientiarum Animal Sciences. 2014;36(2):157-162.
7. Potença A, Murakami AE, Ospina-Rojas IC, Fernandes JIM. Digestible valine-to-lysine ratio in diets for broiler chickens. Revista Mexicana de Ciencias Pecuarias. 2015;6(1):25-37.
8. Rodehutscord M, Fatufe AA. Protein and valine gain of broilers in response to supplemental L-valine. In: Proceedings of the 15th European Symposium on Poultry Nutrition; 2005 Sep 25-29; Balatonfüred, Hungary. World's Poultry Science Association; 2005. p. 545-547.