Effect and mechanism of giutamine on productive performance and egg quality of laying hens

Abstract

This study was conducted to investigate the effects of dietary giutamine (Gin) on the productive performance and egg quality of laying hens. A total of four hundred Lingnan Yellow laying hens aged 34 weeks were randomly assigned into four groups (100 laying hens/group), and fed, respectively, with diets supplemented with 0% (control group), 0.2%, 0.4%, and 0.8% Gin during the 6-week feeding period. The results were as follows. First, the productivity of laying hens fed with 0.8% Gin in diet was significantly increased (p<0.05); however, the egg quality (egg weight, yolk weight, shell weight, egg shape index, shell thickness, shell density, shell breaking strength, yolk color, yolk index, and Haugh unit) was not affected compared with that of the control group (p>0.05). Second, luteinizing hormone (LH) (p<0.01), follicle stimulating hormone (FSH) (p<0.01), triiodothyronine (T3), and tetraiodothyronine (T4) contents (p<0.05) in blood of laying hens fed with 0.8% Gin in diets were also significantly improved, and greater improvement in the duodenum and oviduct structure was observed in that treatment group. Thisstudy indicated for the first time that diets with 0.8% Gin were able to increase the productive performance of laying hens through stimulating hormone secretion and better development of both the duodenum and oviduct structure in laying hens.