Yusuf Cufadar

The effect of dietary calcium concentration and particle size on performance, eggshell quality, bone mechanical properties and tibia mineral contents in moulted laying hens.

1. A total of 72 H&N Brown Nick laying hens, 76 weeks of age (moulted at 60 weeks of age), were randomly assigned into a 3 × 3 factorial arrangement with three limestone particle sizes and three dietary Ca concentrations (30, 36 and 42 g/kg Ca); with 8 replicates per treatments, and one hen (individual) per experimental unit. 2. Particle sizes of the limestone were: distributions smaller than 2 mm (Fine), between 2 to 5 mm (Medium), and larger than 5 mm (Large). The fine, medium and large limestone particles were all obtained from the same source, and sieve sizes used had screen sizes 2 mm and 5 mm. 3. The different concentrations of dietary Ca, particle size or interactions had no significant effect on egg production, egg weight, egg mass, feed intake or feed conversion ratio. 4. The concentrations of dietary Ca and particle sizes had no significant effect on egg breaking strength, eggshell as % by weight of whole egg or eggshell thickness. The interactions between Ca concentrations and particle sizes had a significant effect on eggshell breaking strength, but not on other parameters. 5. Different dietary particle sizes had no significant effect on the Ca, P and Mg mineral contents of eggshell. While the different concentrations of Ca in diets had a significant effect on the P content of eggshell, they had no significant effect on Ca and Mg contents. 6. Different dietary concentrations of Ca had a significant effect on shear stress, and Ca and Mg contents of tibiae, but not other parameters. Also, dietary particle sizes had a significant effect on shear stress and Ca contents of tibiae. The interaction between Ca concentrations and particle sizes had a significant effect on tibia shear force and Ca content. 7. According to the results of this study, moulted brown laying hens should be fed 36 g/kg Ca and a medium limestone particle size (2–5 mm) in the diet to maintain performance, eggshell and bone quality.

Effect of supplementation of different boron and copper levels to layer diets on performance, egg yolk and plasma cholesterol

PROCEDURE This study was conducted to determine the effects of supplementation of different levels boron and copper on performance, lipids in yolk and plasma contains in layer diets. In this trial a total of 320 layer chicken (26 weeks old age) was randomly distributed in 16 experimental groups. In each experiment group were consist at 5 replicates, and in each replicates there were 4 birds. During the 16 weeks experiment period, birds were fed with 16 experimental diets. Experimental diets were consisting of all possible combination of 4 levels of added boron (0, 60, 120 and 240 mg/kg) and 4 levels of added copper (0, 75, 150 and 300 mg/kg) to the basal ration. RESULTS Effect of treatments on body weight change and plasma glucose levels were not significant. However, added boron and copper had a significant effect on plasma high-density lipoprotein cholesterol fraction. While added boron had a significant adverse effect on performance parameters, added copper had a significant positive effect on the same parameters. Yolk lipid contents were increased by addition of boron to the ration. However, yolk lipid contents were decreased by addition of copper to the ration. Plasma lipid contents were also decreased by addition of copper and boron in the ration. CONCLUSION Results of the present study showed that laying hens from 26 to 42 weeks of age should be fed with 60 mg/kg boron and 150 mg/kg copper supplementation in the diet.

Effects of xylanase enzyme supplementation to corn/wheat-based diets on performance and egg quality in laying hens

This study was conducted to determine the effects of xylanase supplementation of corn/wheat-based diets on the performance and egg quality of laying hens. At 52 wk of age, 180 White Leghorn LSL laying hens were fed 15 diets, consisting of five corn:wheat ratios and three levels of enzyme. None of the treatments affected performance or egg quality, except for egg yolk index and egg yolk color. The egg yolk color was improved by the increase in dietary corn level. It is concluded that wheat can be used instead of corn as an energy feedstuff in laying hen diets. Key words: Egg quality, laying hen, performance, xylanase

The effect of replacing soya bean oil with glycerol in diets on performance, egg quality and egg fatty acid composition in laying hens

The objective of this experiment was to replace soya bean oil with glycerol in laying hen diets and assess the changes effect on performance, parameters of egg quality and the egg fatty acid profile. A total of 60 44-week-old Hy-Line W36 laying hens were distributed according to a completely randomised experimental design into four treatments consisting of glycerol substitutions for soya bean oil dietary at varying inclusion levels (0%, 25%, 50% and 75%), with five replicates of three birds each. Dietary treatments had no significant effect on BW change, egg production, feed intake, feed conversion ratio, egg weight and egg mass of laying hens. The inclusion of glycerol in the diet of laying hens had no significant effect on egg specific gravity, eggshell breaking strength, eggshell weight, eggshell thickness, egg shape index, albumen index, yolk index, haugh unit, albumen pH, yolk pH and egg yolk colour values. The inclusion of glycerol in the diet of laying hens had no significant effect on palmitic, palmitoleic, stearic, oleic and linolenic acid contents of the egg yolk. The linoleic acid and polyunsaturated fatty acid contents of the egg yolk significantly decreased with the higher levels of dietary glycerol supplementation (P<0.05). The results of this study show that it is possible to replace 75% of soya bean oil (4.5% in diet) with glycerol.

The effects of eggshell and oyster shell supplemental as calcium sources on performance, eggshell quality and mineral excretion in laying hens

A study was conducted to determine the influence of different calcium sources in layer diets on performance, eggshell quality and mineral excretions. A total of 72 Hy-Line W36, layer birds of 25 weeks old, were distributed in 6 experimental groups randomly. In each experiment group there were 4 replicates, and in each replicates there were 3 birds. During the 12 weeks experiment period, birds were fed 6 experimental diets. Experimental diets were consisted of various calcium sources for meeting the calcium requirements. It was control (limestone), 1/3 eggshell, 1/3oyster shell, 1/3 eggshell+1/3 oyster shell, 2/3 eggshell and 2/3 oyster shell. Dietary different sources of calcium had no significant effect on body weight change, feed conversion ratio, eggshell breaking strength, eggshell thickness, and eggshell phosphorus and magnesium contents (p > 0.05). The different sources calcium had a significantly effect on egg production, egg weight, egg mass, feed intake and eggshell weight in laying hens (p