Nutritive value of high-oil corn grown under semi-arid conditions and its impact on broiler performance and carcass composition.

A series of experiments was conducted to evaluate nutritive value of a high-oil corn (HOC) cultivar, grown under semiarid conditions, and its impact on performance and carcass characteristics of male broilers raised to market age. Conventional corn (CC) and HOC used in this research were produced under similar semi-arid conditions. By using a glucose containing reference diet in Experiment 1, the AMEn of CC, as determined on 11-d-old male broilers, was lower (P < 0.05) than that of HOC (3,541 vs. 3,669 kcal/kg DM). The TME, TMEn, and true amino acid availability of CC and HOC were determined in Experiment 2 through individual precision feeding of eight intact mature roosters per ingredient. The TMEn of HOC was significantly higher than that of CC (4,126 vs. 3,870 kcal/kg DM), but true availability of amino acids was comparable for both cultivars. By using the CP and TMEn values determined in Experiment 2, two corn soybean meal starter and grower diets, containing no added fat, were prepared in Experiment 3, in which HOC replaced CC. Diets were provided ad libitum in five replicates to 5-d-old male broilers with eight birds per replicate until market age. Broiler performance, carcass yield, and carcass composition were comparable between both corn cultivars. Birds on HOC diet, however, deposited more (P < 0.05) abdominal fat (0.695%) than those on CC diet (0.575%). The results indicated that the extra calories derived from HOC could have been funneled primarily toward abdominal fat pad deposition rather than increased growth.

Induction of early immunopotentiation to Fimbriae of Salmonella Enteritidis (SE) by administering thymulin and zinc to SE-vaccinated chicken breeders: relationship to protection.

The purpose of this study is to attempt the induction of early immunopotentiation of antibodies specific to fimbriae of Salmonella enterica serovar Enteritidis (SE), by administering thymulin and zinc to SE-vaccinated chicken breeders, and the improvement of protection against a controlled-live challenge by SE. The first two groups of breeders were administered subcutaneously at 15 and 19 weeks of age a killed SE vaccine. Breeders of the third and fourth groups were left unvaccinated. Breeders of the first group, immunopotentiated by thymulin and zinc, were able to induce the earliest antibodies in their pooled sera at 2 weeks post the first SE-vaccination, specific to fimbriae (approximately 21 KDa) of SE. However, the second group that was only vaccinated with the same SE-vaccine produced specific antibodies to fimbriae at 3 weeks following the second vaccination (22 weeks of age). Breeders of the third group, that were neither SE-vaccinated nor immunopotentiated by thymulin and zinc, but were challenged by live SE at 22 weeks of age, were able to show specific antibodies to fimbriae at 3 weeks post challenge (25 weeks of age). The fourth group that was deprived of SE-vaccination, immunopotentiators, and challenge didn't show any background antibodies specific to SE-fimbriae. The presence of the earliest antibody-immunopotentiation to fimbriae of SE in breeders of the first group, administered thymulin and zinc, was associated with the lowest frequency of SE-infected ceca (10%) among the challenged groups. In addition, breeders of the first group were the only challenged birds resulting in absence of SE infection in their cecal tonsils. The first group-vaccinated, immunopotentiated, and challenged, and the second group-vaccinated and challenged only resulted in breeders with absence of SE infection in their oviducts and spleens. In conclusion, immunopotentiation of chicken breeders by thymulin and zinc induces the earliest specific antibodies to fimbriae of SE associated with the lowest frequency of SE-infected ceca, and absence of SE infection from cecal tonsils, oviducts and spleens.

Chronological recognition by chicken of antigenic polypeptides in Salmonella enteritidis with different plasmid profiles: relationship to infection rate.

The antigenic polypeptides in Salmonella Enteritidis (SE) were chronologically recognized by the chicken immune system, using Western immunoblotting. Broiler chicks challenged at three days of age with SE strain carrying the most prevalent plasmid profile of 14.1 and about (approximately) 50 kb were bled at 17, 24, 31, 38 and 45 days of age. Pooled sera of blood collected at each age was reacted by Western immunoblotting with banded polypeptides of three predominant SE strains that acquired the following respective plasmid profiles: 14.1 kb; 14.1 and approximately 50.0 kb; and 1.8, 14.1 and approximately 50.0 kb. The immunoblots of each pooled sera collected at a specific age against the three SE strains were similar. More specifically, the early immune response at 17 days of age had antibodies recognizing only one polypeptide in the three SE strains namely, the 35.8 kDa. At 24 or 31 days of age, the acquired immunity to infection had antibodies recognizing five similar polypeptides in the three SE strains namely, the 14.4 (fimbriae protein), 21.5 (fimbriae protein), 30.5, 35.8, and 66.2 kDa. At 38 and 45 days of age, the antibodies recognized additional polypeptides namely, the 41.5 and 55.6 kDa, respectively. The recognition of the 41.5 and 55.6 kDa polypeptides at 45 days of age was associated with higher invasiveness of SE to spleens and livers (15.6%) and in higher cecal colonization (59.4%) in comparison to absence of recognition to the two polypeptides at 31 days of age associated with low infectivity to spleens (0%), livers (3.1%), and ceca (9.4%).

The effect of 1 alpha,25-dihydroxyvitamin D3 added to a layer diet containing adequate amounts of vitamin D3 on the performance of layers.

The effect of adding 1 alpha,25-dihydroxyvitamin D3 (calcitriol) to a well-balanced, commercial layer diet containing 1,900 IU vitamin D3/kg on eggshell quality and laying performance of 56-wk-old White Leghorn hens was investigated. After 8 wk of treatment, calcitriol at 1.5 micrograms/kg diet had no discernible effect on egg weight, egg deformation, percentage shell, shell thickness, feed consumption, and egg production. At 3.0 and 4.5 micrograms/kg, feed consumption, feed production, and egg weight were significantly reduced, whereas egg deformation, percentage shell, and shell thickness were not affected. The results show that calcitriol added to a diet already adequately supplemented with vitamin D3 does not improve eggshell quality and may impair laying performance.

Phosphorous requirements of laying hens in a semiarid continental climate.

Single Comb White Leghorn layers raised in floor pens in conventional open housing were used to determine their phosphorous requirement in a semiarid continental climate. Dietary available phosphorous (AP) of .15, .25, .35, and .45% were fed continuously from 26 to 74 weeks of age. Concurrently, diets containing .45, .35, and .25% AP or .35, .25, and .15% AP were "phase fed" during the age intervals of 26 to 42, 42 to 54, and 54 to 74 weeks, respectively. Diets used were corn-soybean diets in which the phosphorous was varied by changing the level of dicalcium phosphate in the ration. Under the conditions of this experiment, hens required a minimum of .25% AP for best egg production, feed consumption, and body weight gain. The AP levels above .35% depressed shell thickness. In a phase-feeding program, when the last phase corresponds with the summer season, AP should not go below .25% for best performance.

Effect of lysine and methionine supplementation of low protein roaster diets fed after six weeks of age.

Three floor rearing experiments were conducted using male broilers to determine the extent to which the protein level of the diet can be reduced by supplementation with the amino acids methionine and lysine. Corn-soybean type diets were used and three protein levels (18, 15, and 12%) were tested. All rations were computer formulated and those containing 15 and 12% protein were supplemented with DL-methionine and L-lysine HCl. Three replicate pens of about 50 males per pen were assigned to each treatment. Experimental diets were fed from 6 to 10 weeks of age in Experiment 1 and 6 to 9 weeks in Experiments 2 and 3. Birds were all group weighed at weekly intervals and feed consumption determined. Results obtained in Experiments 1 and 3 showed that neither body weight nor feed efficiency was reduced by feeding either 15 or 12% protein diets as long as these diets contained the National Research Council (NRC, 1977) recommended level of methionine and lysine. In Experiment 2 the 12% protein level depressed body weight and feed efficiency. Net returns over feed cost were highest with the 15% protein level in all three experiments. These results indicate that the NRC (1977) recommendation of 18% protein for 6- to 9-week-old broilers may be reduced with adequate amino acid supplementation.

Vitamin B6 in the etiology of gizzard erosion in growing chickens.

Six experiments have been completed on day-old male cross-bred chicks for periods of up to 2 and 4 weeks to learn more about the role of pyridoxine in the etiology of gizzard erosion. At the end of each experiment, chicks were sacrificed and their gizzards removed and scored for the severity and incidence of erosion. The results of these experiments confirm the previous finding that the severity and incidence of gizzard erosion is increased by B6 deficiency. They further show that taurocholic acid, at 1% of the diet, had a protective effect against this erosion. Feeding B6-adequate rations to chicks that previously had been fed a B6-deficient diet led to partial healing of gizzard erosions. Results also indicate that the feeding of purified diets to growing chickens produces a higher incidence of erosion than that of practical-type diets. Texture of the diet did nt influence the incidence of the erosion, because grinding a practical diet to the same fineness as a purified diet did not increase gizzard erosion. Pair-feeding experiments showed that gizzard erosion in partially starved chicks was not a specific result of anorexia but of deficiencies in certain nutrients, one of which is vitamin B6.

Blood constituents of yeast fed chicks.

Two experiments on broiler chicks raised to 4 weeks of age were carried out to study the effects of replacing soybean protein in a semisynthetic diet with yeast protein from molasses (CEPAH). Criteria measured were body weight, feed efficiency, plasma urea nitrogen, serum uric acid, serum total protein, albumin, globulin and albumin-globulin ratios. Analysis of the data showed that yeast protein produced from molasses depressed growth and feed efficiency at levels 10, 15, and 20% of the diet. The effects of yeast protein on blood nitrogenous constituents were variable and not significant, but in general, the inclusion of yeast protein caused an increase in serum albumin and a decrease in serum globulin resulting in a higher albumin-globulin ratio. The changes observed in blood nitrogenous constituents in this study do not explain all the detrimental effects of yeast protein on growth and feed efficiency of chicks receiving high levels of such protein.

Metabolizable energy (M.E.) values of three protein supplements as determined with chicks and laying hens.

The M.E. values of three protein supplements that are produced and/or processed in Lebanon and Jordan were determined employing the method of Hill and Anderson (1958). Two experiments were conducted using broiler-type chicks in one experiment and White Leghorn laying hens in the other experiment. Nitrogen-corrected M.E. values expressed in kcal./kg. dry matter were found to be 2513, 2690 and 3215 for the soybean, sesame and poultry by-product meals, respectivel, as determined with chicks, and 2522, 2747 and 3155 as determined with laying hens. Hence, it was concluded that chicks were as efficient as laying hens in energy utilization of these protein supplements. For all practical purposes, it was recommended that metabolizable energy values, of commonly used protein supplements, determined with either chicks or laying hens could be used in poultry ration formulation.