In the present feeding trial,responses of laying hens that were kept at high ambient temperature and Fed with various dietary ratios of linoleic acid(LNA)toα-linolenic acid(ALA)and vitamin A levels on production perf...In the present feeding trial,responses of laying hens that were kept at high ambient temperature and Fed with various dietary ratios of linoleic acid(LNA)toα-linolenic acid(ALA)and vitamin A levels on production performance and egg quality traits were evaluated.A total of 360 Leghorn laying hens at 40th week of age(average initial body weight;1.79±0.23 kg)were fed with various combinations of canola oil and linseed oil containing diets to achieve LNA to ALA dietary ratios of 20:1,10:1,4:1,2:1,1:1 and 1:2,each supplemented with 3000 or 10000 IU of vitamin A/kg of diet.The experiment was designed as a 6×2 factorial Completely Randomized Design that continued for 12 weeks.Feed intake,body weight gain,egg production and egg quality traits were recorded during the trial.Decreasing dietary LNA to ALA ratio or increasing poly unsaturated fatty acids(PUFA)in the diet decreased(P<0.05)body weight gain and yolk percentage in laying hens.Feed intake,hen-day and hen-housed egg production,feed conversion ratio(FCR)per dozen of eggs and shell quality remained unaffected(P>0.05)by dietary treatments.Feed conversion ratio per kg eggs,egg weight and egg-shell thickness showed a curvilinear(P<0.05)response to decreasing dietary LNA to ALA ratio.Although the dietary ratio of LNA to ALA of 4:1 or less could produce eggs by the hens with desirable quantities of n-6 and n-3 PUFA–that are characteristics of functional diets–the performance of laying hens in terms of body weight gain and egg-yolk percentage was slightly compromised.Therefore,a 4:1 or 2:1 LNA to ALA combination can make a borderline between the production traits and the feed economics.展开更多
文摘In the present feeding trial,responses of laying hens that were kept at high ambient temperature and Fed with various dietary ratios of linoleic acid(LNA)toα-linolenic acid(ALA)and vitamin A levels on production performance and egg quality traits were evaluated.A total of 360 Leghorn laying hens at 40th week of age(average initial body weight;1.79±0.23 kg)were fed with various combinations of canola oil and linseed oil containing diets to achieve LNA to ALA dietary ratios of 20:1,10:1,4:1,2:1,1:1 and 1:2,each supplemented with 3000 or 10000 IU of vitamin A/kg of diet.The experiment was designed as a 6×2 factorial Completely Randomized Design that continued for 12 weeks.Feed intake,body weight gain,egg production and egg quality traits were recorded during the trial.Decreasing dietary LNA to ALA ratio or increasing poly unsaturated fatty acids(PUFA)in the diet decreased(P<0.05)body weight gain and yolk percentage in laying hens.Feed intake,hen-day and hen-housed egg production,feed conversion ratio(FCR)per dozen of eggs and shell quality remained unaffected(P>0.05)by dietary treatments.Feed conversion ratio per kg eggs,egg weight and egg-shell thickness showed a curvilinear(P<0.05)response to decreasing dietary LNA to ALA ratio.Although the dietary ratio of LNA to ALA of 4:1 or less could produce eggs by the hens with desirable quantities of n-6 and n-3 PUFA–that are characteristics of functional diets–the performance of laying hens in terms of body weight gain and egg-yolk percentage was slightly compromised.Therefore,a 4:1 or 2:1 LNA to ALA combination can make a borderline between the production traits and the feed economics.
