Studies on immune response, nutrient utilization and blood biochemical profile as influenced by dietary supplements of vitamins and minerals in broiler chicken

Thesis Abstract

Title of the Thesis:

Studies on immune response, nutrient utilization and blood biochemical profile as influenced by dietary supplements of vitamins and minerals in broiler chicken

The effect of supplementation of vitamins (A+E) and minerals (selenium+zinc +chromium) individually or in combinations in the diet of 240 day-old Ross 308 broiler chicken  on the growth performance, nutrient utilization, carcass characteristics, biochemical profile, hematological parameters, immunological response and anatomical features were studied. The starter (0-14 d) diets were formulated to contain 23% CP and 2900 kcal ME. Grower's diet contained 21.5% CP and 3000 kcal energy while in the finisher stage the diets were constituted with 3100 kcal ME/kg and 20% CP. The level of supplementation of these nutrients in all the stages remained same. Diets were formulated using maize, deoiled rice bran, deoiled soybean cake, fish meal feed ingredients. All diets were supplemented with vitamins and minerals premixes in addition to DL methionine, common salt and lysine. The dietary treatments were arranged in a 2x 3 factorial design where two variables indicate the level of vitamins (zero level A+E; A 11000 IU/kg+ E 300 mg/kg) and three variables indicate the levels of minerals [zero level Se+ Zn +Cr (T1); Se 0.15+Zn 25 +Cr 0.30 ppm (T2); Se 0.20+Zn 50+Cr 0.50 ppm (T3)].

The data were recorded for weekly DM intake, body weight gain, feed conversion ratio and carcass characteristics up to 6 weeks of age. At 42 days a 3 days metabolism trial was also conducted for balance study.

During 28-35 days the highest weekly weight gain was recorded in T₃ (648 g) followed by T₆. At 42 days broiler chicken attained highest total body weight of 2451g in T₆, followed by T₅ (2424g) and T₃ (2401g). The feed conversion ratio was best in T₃. Balance study showed no significant difference amongst groups due to supplementation of minerals and vitamins on N, Ca and P balance. The dietary supplementation of minerals did not affect the level of serum Cr however Se, Zn and Cu increased significantly (p<0.05) in T₂ and T₆ as compared to their controls.

 The dressing percentage was found highest (77.70 %) in T₃. There was a significant reduction in the total serum cholesterol in mineral + vitamins supplemented group (T₆) followed by T₃. In contrary the HDL-cholesterol during the same period was found maximum in T₆ followed by T₃. The cholesterol level continued to reduce up to 42 days while during this period serum HDL-cholesterol increased to a maximum level in T₃.  There was significant (P<0.05) difference amongst groups in Hb concentration at 28 days, it was maximum in T₆. The H/L ratio was lowest in T₃ both at 28 and 42 day.

Supplementation of exogenous vitamins and minerals had significant (P<0.05) effect on immunological response especially serum HI titers against Newcastle disease virus and skin thickness index against DNCB, both were recorded highest in T₆.

There was significant (P<0.05) increase in organ weight factor of bursa, spleen and thymus in vitamin supplemented group as compared to other groups. The medulla and cortex of bursa were found compact and densely organized in T₂ and T₅ as compared to their respective control. In T₂ and T₆ white pulp of spleen was compactly organized and nodular arteriole of their white pulp was more developed than other treatments. In intestine solitary lymphatic nodules were seen in different groups.

The net profit (Rs/kg) in broiler raising from 0 to 42 days was maximum in T₃ and T₆.  It could be inferred that supplementing minerals (Se +Zn +Cr) at the level 0.20+50+0.50 ppm respectively or in combination with vitamin (A +E) at the level 11000 IU/kg +300 mg/kg respectively were found most economical in raising broiler chicken.