فهرست مطالب فائزه سادات کیاءالحسینی

In recent decades, with the ban on the use of antibiotics in the poultry industry, the use of new alternatives such as probiotics and prebiotics have increased. Some of these alternatives can improve the growth and health of birds by creating optimal changes in the microbial population of the digestive tract. Therefore, the present experiment was conducted to investigate the effect of kappa-carrageenan polysacharid and primalac probiotic on the growth response and health of broilers.

240 one-day-old broilers of Ross 308 strain in a completely randomized design with 2× 2 factorial arrangement, including two levels of probiotic additive (zero and 0.1 % of food ration) and two levels of kappa-carrageenan additive (zero and 0.1 % of food ration) distributed in 24 cages (six replicates each containing ten birds) and reared on floor system for 24 days.

The growth performance of birds was not affected by the interaction of probiotics and kappa-carrageenan in the diet. However, the use of kappa-carrageenan in diets significantly increased the body weight gain of birds during 1 to 10 days of age. Feed intake of the birds was not affected by the experimental treatments and dietar levels of probiotic and kappa-carrageenan, but the feed conversion ratio was improved by adding 0.1% of probiotic in the diet at day 24 (P< 0.05). The relative weight of thigh in birds that received kappa-carrageenan was higher compared to the zero level of kappa-carrageenan in the diet (P< 0.05). Probiotic supplementation alone in the diet increased the relative weight of the liver of birds. Also, the relative weight of the liver was significantly lower in the birds that received diets containing kappa-carrageenan. In broilers fed with kappa-garakinan, the villus length increased in the duodenum and decreased the crypts depth in the ileum. The use of 0.1% of probiotics significantly increased the population of lactic acid bacteria in the ileum of birds. The population of lactic acid bacteria in the ileum of birds under 0.1% of probiotic increased significantly. Consumption of kappa-carrageenan and probiotics separately or mixed in the diet reduced the population of coliforms in the cecum (P< 0.05). Using a mixture of kappa-carrageenan and probiotic in the diet the activity of superoxide desmutase enzyme improved compared to the treatment containing kappa-carrageenan (P< 0.05).

The results of the present experiment showed that the use of probiotics and kappa-carrageenan in the diet of young broiler chickens can be effective in improving some parameters of the growth response during separate periods of rearing and optimally changing the microbial population of the digestive tract.