Two experiments determined the effect of dietary riboflavin supplementation on egg yolk and albumen riboflavin concentrations, egg production, egg weight, shell thickness, hen weight, hatchability, incidence of clubbed down, and incidence of hemorrhagic embryos. In the first experiment, hens were fed rations containing 1.55, 2.20, 4.40, and 8.80 mg of riboflavin/kg of diet for 27 wk. Significant (P < .05) depressions in both yolk and albumen riboflavin concentrations were noted at the two lower riboflavin levels after 1 wk. Egg production, egg weight, hatchability, and hen weight were all significantly depressed by the two lower riboflavin levels later in the experiment when compared with the two higher levels. Results indicate that egg riboflavin concentrations are related to important production parameters that may be used to predict future dietary riboflavin inadequacies. In the second experiment, hens were fed either an unsupplemented diet or a riboflavin-adequate diet. Measurements of egg albumen riboflavin content, egg production, hatchability, and embryo abnormalities were made twice each week. Results showed depressed albumen riboflavin concentrations and hatchability and increased incidence of hemorrhagic embryos and clubbed down without changes in egg production during the 4- to 7-day period following feeding of the unsupplemented diet. These results show that low albumen riboflavin content immediately affect hatchability and embryonic development. The estimated minimum critical albumen riboflavin concentrations needed to support maximum reproductive function are between 1.9 and 2.9 micrograms of riboflavin/g of egg albumen. These critical values might be used to evaluate riboflavin status of laying and breeding flocks.
Laying hens were fed deficient diets, unsupplemented or supplemented with one, two, or four times the National Research Council requirement level of vitamin A for 27 wk. Vitamin A levels of egg yolk from hens fed the unsupplemented diet slowly declined but levels of vitamin A stabilized at 12 wk in the supplemented groups and were related to dietary level. Egg production of hens fed the unsupplemented diet declined significantly after 12 wk and egg yolk levels continued to decline to Week 27. Hatchability of eggs laid by the unsupplemented hens was significantly lower at Weeks 25 and 26 than hatchability for those hens receiving dietary vitamin A. Hen weight, egg weight, and shell thickness were not consistently changed by treatment. In a second experiment, hens were fed a diet with and without 9,000 IU vitamin A/kg of diet. With birds receiving the supplemented diet, egg yolk vitamin A levels were stable after 13 wk, whereas egg yolk levels from unsupplemented hens declined slowly. Egg production with the unsupplemented diet was significantly reduced after 16 wk but the magnitude of the reduction was less than that in the first experiment, although egg vitamin A levels were as low as those in the first experiment. Hatchability of eggs during Weeks 25 to 28 was greatly reduced. Egg weight, albumen score, and chick weight were not consistently altered by vitamin A status. Because declines in egg yolk vitamin A do not precede declines in egg production they are not useful to predict future vitamin A deficiency in laying hens.
Two experiments were conducted to determine the effects of heat, water, acid, and alkali treatment of tomato pomace on gain, feed to gain ratio, nitrogen utilization, and ME of diets for broiler chicks. In Experiment 1, both treated and untreated tomato pomace was included in broiler diets at a 10 or 20% level. Results indicated that the level or antinutritional factors present in untreated tomato cannery waste did not appreciably depress any measured production parameter. Hence, it appeared that untreated tomato cannery wastes might be used as a feed ingredient in low-energy poultry diets (broiler breeder and laying hen recycling rations), ruminant diets, and as a protein source in regions of the world where such feed ingredients are scarce. The second experiment was designed to test the effect of alkali concentration and treatment time of tomato pomace on the performance of broiler chicks. Alkali treatment of tomato cannery wastes increased gain and decreased feed to gain ratios of broiler chicks over those of untreated tomato waste controls. Results indicated that the increased gain and decreased feed to gain ratios of the chicks were due in part to the acid neutralization phase of the alkali treatment. Alkali treatment apparently affects the tomato cannery wastes almost instantaneously, as differences among actual treatment times and concentrations were small. However, only the highest alkali treatment increased the pH of the tomato cannery waste above 7, suggesting that a true alkali treatment might cause additional improvements in gain and feed to gain ratio when fed to broiler chicks.
Four groups of laying hens were fed a corn and soybean meal basal diet without vitamin supplementation, with riboflavin, with other vitamins, or with riboflavin and other vitamins for 3 wk. They were then fed a recovery diet for 1 wk. Egg production rate was unaffected by the absence of vitamin supplements. Egg weight was significantly reduced by riboflavin deficiency and the absence of other vitamins and further reduced by the absence of both riboflavin and the other vitamins. Egg hatchability was markedly reduced by riboflavin deficiency in the presence or absence of other vitamins. Egg albumen riboflavin concentrations dropped within 4 to 6 days in eggs from hens fed the diets without riboflavin or all supplemental vitamins. Albumen color scores in eggs from hens fed diets without supplemental riboflavin dropped in 2 days and continued to decline. The correlation coefficient of egg albumen riboflavin content with egg albumen color score was very high (r = .96). It appears that egg albumen riboflavin concentrations or egg albumen color scores can be used not only to assess nutritional status of the hen for this vitamin but also as a quality control measure in feed formulation and mixing for the presence of vitamin supplements in the diet.(Key words: detecting vitamin deficiency, albumen riboflavin, albumen color score, layers, egg weight)
Hens of a type used for egg production were fed a corn and soybean meal diet supplemented with no vitamin B12 or with vitamin B12 levels to provide one, two, or four times the National Research Council (1984) breeding hen requirement of 4 micrograms/kg diet for 27 wk. All hens were placed on a recovery diet containing one and one-half times the requirement level of vitamin B12 from Weeks 27 through 30. Egg yolk vitamin B12 concentrations were determined frequently by radioisotope dilution analysis. Egg production records were kept continuously, and eggshell thickness, egg weight, hatchability of eggs, and hen body weights were measured at selected times. Although egg yolk vitamin B12 concentrations were high at the outset, they decreased markedly in 2 wk from hens fed the two lowest dietary levels. After 12 wk on the diets, egg concentrations of vitamin B12 stabilized and were proportional to the amount of vitamin added to the diet. Egg concentrations of vitamin B12 between 1.3 and 2.6 micrograms/100 g yolk appeared to be needed to support maximum hatchability and egg weight. Egg production was reduced after 12 wk on the diets in the hens fed the two lowest vitamin B12 levels. As vitamin B12 level increased, shell thickness decreased and egg weight, hen weight, and hatchability increased. Maximum egg production, egg weight, hen weight, and hatchability were obtained when the diet contained 8.0 micrograms/kg of vitamin B12. Egg yolk vitamin B12 concentrations respond rapidly to dietary changes in the level of this vitamin and are indicative of the vitamin B12 status of the hen.
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