Effects Of Different Dietary Crude Protein Levels On The Laying Performance And Egg Quality Of Huafeng Layer

The present experiments was conducted to study the effects of different dietary crude protein levels on egg laying performance, apparent metabolic rate of nutrients, egg quality and physical and chemical indicators of blood in the egg peak of Huafeng layer.108027-week-old healthy Arbor Acre Huafeng layer were selected and randomly allotted into6treatments, each treatment consisted of three replicates with60broilers in each replicate. Six treatments included group1,2,3, these three groups were pure soybean meal diet and protein levels were15.5%、16.5%、17.25%, group4,5,6, these three groups used cottonseed meal and rapeseed meal to substitute part of soybean meal, protein levels were the same as group1,2,3. The feeding trial lasted8weeks. The experimental diets and water were available ad libitum during the entire experimental period.Experiment1:Effects of dietary different protein levels on the laying performance in the period of28-34week of Huafeng layerRecording egg number, the number of abnormal eggs, egg weight, eggshell color and dead layers everyday; weighting the total and the remaining quantity of feed, the average egg weight of the repeating groups every week (the average for three consecutive days, within24hours) and the actual feed intake; in the positive test period,. Calculation of egg production,abnormal eggs ratio; egg weight, feed consumption volume, feed conversion ratio; death rate and so on.Under this different levels ofprotein, miscellaneous meal diet had significant effect on the egg production, feedegg ratio, feed consumption of Huafeng layer (P<0.05). Different protein levels showed no effect on egg weight, broken egg rate of Huafeng layer (P>0.05)6group diet was metabolic energy for11.26MJ/Kg and protein level for17.25%and the diet was suitable for the peak of egg production.Experiment2:Effects of dietary different protein levels on the apparent metabolic rate of nutrients in the period of28-34week of Huafeng layer.Six layers (3male,3female) from each repeating group in the initial stage and the final stage of the experiment were selected as experimental animals to study apparent metabolization ratio ofprotein in diet.With the improvement ofprotein, protein, energy, dry matter and the apparent metabolism of calcium and phosphorus also increased under the different levels of protein, at the same time the miscellaneous meal diet group was higher than pure soybean meal group.6group diet was metabolic energy for11,26MJ/Kg and protein level for17.25%and the diet was suitable for the peak of egg production.Experiment3:Effects of dietary different protein levels on the egg quality in the peak of egg production of Huafeng layerIn the initial stage and the final stage of the experiment, each group randomly collected five eggs and continued to collect3d. Determining eggshell color, measuring longitudinal diameter、 transverse diameter, determining eggshell strength, shell thickness, albumen height, yolk color and the weight of eggshell, lbumen, yolk and other egg quality parameters.According to theprotein levels of this experiment, different levels ofprotein were no significant difference in the eggshell color, eggshell strength, eggshell percentage, shell thickness in the early stage of the test (P>0.05). Different levels ofprotein had no significant effect on egg shape index、egg weight、albumen ratio、yolk proportion and yolk color in the early stage of the test (P>0.05). With the rise of protein level, pure soybean group and miscellaneous meal group’s amino acid content of eggs respectively improved, and amino acid content of pure soybean group was higher than miscellaneous meal group. With the improvement of protein, egg yolk saturated fatty acid content decreased, and egg yolk saturated fatty acid content of miscellaneous meal group was lower than pure soybean group. Based on improvement of protein, no significant differences between moisture, protein, fat content of the eggs (P>0.05), cholesterol of egg had a escalating trend, and content of pure soybean group was significantly higher than miscellaneous meal group (P<0.05).Experiment4:Effects of dietary different protein levels on the blood indices in the28-34week period of Huafeng layerSix layers (3male,3female) from each repeating group in the initial stage and the final stage of the experiment were selected as experimental animals to collected venous blood from the wing root, then the samples were sent to the hospital to determine physical and chemical indicators of blood.The results showed that in the early and late stages, the differentproteinal levels had no appreciable impact on serum total protein, albumin and globulin, glutamic-oxalacetic transaminease (GOT), glutamic-pyruvic transaminase (GPT), lactate dehydrogenase (LDH), alkaline phosphatase enzyme (ALP), serum pH, Ca2+, P3+and so on (P>0.05). Different protein levels had no significant effect on blood sugar, uric acid, total cholesterol levels in the early stage (P>0.05), urea nitrogen content was on a declining curve. Besides, the content of miscellaneous meal group was lower than pure soybean group, group5and6were significantly lower than the other four groups (P<0.05), triglyceride content decreased, the content of miscellaneous meal group was lower than pure soybean group, group6was significantly lower than group1(P<0.01); each index in the final test showed no significant difference (P>0.05).