Effects Of Different Dietary Cotton Meal Contents On Performance, Egg Quality And Plasma Biological Parameters Of Layers

Two experiments were conducted to evaluate the effects of different levels cotton meal and the molar ratio of free gossypol (FG) to Fe²+ in the layer dietary on the performance, egg quality and plasma biological parameters.Exp.1 studied the effects of different levels cotton meal on the performance, egg quality and plasma biological parameters. 315 new-roman layers with 38 weeks of age were allotted to 7 treatments, per treatment with five pens, per pen with nine layers. The contents of cotton meal (contained FG 1285mg/kg) in the dietary were 0%, 2.33%, 4.67%, 7%, 9.34%, 11.67% and 15.56% respectively, and the levels of FG were Omg/kg, 30mg/kg, 60mg/kg, 120mg/kg, 150mg/kg and 200mg/kg respectively. The trail period lasted 3weeks. The results showed that the performance, egg quality, and plasma biological parameters were decreased gradually with the increase of FG in the dietaries. In the treatment with 200mg/kg FG, the yolk color, GOT, globulin and total protein decreased significantly (p<0.05). The concentration of Fe²+ in plasma decreased (p<0.1). The ratio of albumin to total protein increased (p<0.1).Exp.2 studied the effects of different ratio of Fe²+ to FG in the dietary on the performance, egg quality and plasma biological parameters. 225 new-roman layers with 38 weeks of age were allotted to four treatments, per treatment with five pens, per pen with five lays. Different levels FeSO₄.7H₂O were added to the basis diet with 15.56% cotton meal, the content of Fe²+ in the dietary were Omg/kg, 200mg/kg, 300mg/kg, 400mg/kg, and the ratio of Fe²+ to FG were 0:1, 1:1, 1.5:1 and 2:1 respectively. The results showed that the supplementation of Fe²+ decreased the toxic actions and improved the performance oflayers. The addition of Fe2+ (200mg/kg) had the best effects (p<0.1). Supplementation 400mg/kg Fe2+ increase yolk color (p<0.1). Compared to control treatment, the addition of Fe + had no significant effect on the plasma content of Fe2+, ALP, GOT, globulin, albumin and the ratio of albumin to total protein.IMPLICATION: Different levels of cotton meal in dietary of layers, with the content of FG from 30mg/kg to 200mg/kg, had the negative effects on performance, egg quality and plasma biological parameters. The maximum content of FG in layers dietary can not higher than 30mg/kg dietary. The supplement of FeSO4.7H2O can improve egg quality and plasma biological parameters, and the optimum ratio of Fe2+ to FG was 1:1.