No abstract

No abstract

No abstract

Diets containing either 22 or 30% protein were supplemented with a vitamin mix where one of 11 added vitamins were singly eliminated from the mix. Male, day-old broilers were fed these diets to 3 weeks of age, and weight gains, feed utilization, and leg problems were recorded. In general, the higher protein diet did not result in a greater incidence of leg problems; however, it did alter performance of several of the vitamin-deficient diets as compared to the lower protein diet. Of the 11 vitamins studied only nonsupplementation of riboflavin markedly reduced weight gain and feed utilization during the 3-week feeding period. However, deletions of vitamin D3 and niacin also resulted in reduced performance. Riboflavin deficiency resulted in paralysis in a high percentage of the birds while the niacin-deficient diet gave a high percentage of birds with deformed legs and problems of mobility. The results demonstrate that a high incidence of leg problems may be present in a flock with little or no signs of reduced gain or feed utilization. The data suggest that under practical conditions the elimination of a particular vitamin from a diet for a short period of time would probably have a negligible effect on performance.

Hens, 59 weeks of age, were offered a corn, soya-type diet with no supplemental vitamin D 3 for a 28-day period. Egg production remained relatively constant to the end of the second week and then began to fall precipitously.Egg shell weight remained constant for 10 days, and then a marked linear decrease took place. Shell membrane weight and egg weight were not influenced by a reduction in shell weight. Older hens, or hens previously subjected to a vitamin D 3 deficient diet, seemed better able to cope with a subsequent vitamin D 3 deficiency. (