W. L. Marusich

Effect of coccidiosis on pigmentation in broilers.

Synopsis Broiler chicks were fed on a high energy, commercial‐type ration with 20 g oxycarotenoids/ton1 for 5 weeks. They were then transferred to two finisher rations: one with 20 g oxycarotenoids from the ingredients plus 3 g canthaxanthin/ton; the other containing 26 g oxycarotenoids/ton derived solely from the ingredients. Three replicated groups fed on each finisher ration were inoculated daily for 5 d with either 6000 sporulated oocysts of E. maxima, 30,000 sporulated oocysts of E. acervulina or no coccidial oocysts. The resultant mild infections caused reduced growth and impaired food conversion irrespective of the ration fed. Pigmentation, based on shank visual scores, plasma and toe‐web total carotenoid concentrations, was adversely affected in all infected groups. Groups fed canthaxanthin had higher visual scores than comparable groups not so supplemented; however, the presence of coccidiosis depressed flesh pigmentation proportionately in both groups judged by several pigmentation parameters. E...

Provitamin a activity and stability of β-carotene in margarine

SummarySamples of synthetic β-carotene have been assayed for vitamin A activity by the rat-curative, growth method against vitamin A acetate and compared with natural carotene. The U.S.P. XIV diet was modified by the addition of vitamin B12 and α-tocopherol, which have been reported to enhance carotene utilization. Doses of vitamin A and carotene were given in cottonseed oil and in margarine; but, contrary to the report of Deuelet al. (13), no significant increase was observed in the utilization of carotene fed in margarine. The samples tested include crystalline all-trans β-carotene, micropulverized all-trans β-carotene in an oil suspension, and a series of 10 commercial margarines fortified with vitamin A. and carotene in a ratio of about 2 I.U. of vitamin A to 1 I.U. of carotene.In terms of vitamin A activity in the rat bioassay, the average potency of β-carotene in three separate bioassays of crystalline carotene was found to be 1,730,000 I.U. per gram with a standard error of ±3.5%. Thus in these assays 1 I.U. of vitamin A activity was found to be equivalent to 0.58 mcg. of all-trans β-carotene, a value in essential agreement with 0.6 mcg., the presently accepted International Standard. For margarine samples containing vitamin A and β-carotene, the average vitamin A activity in 2 bioassays was found to be very close to that calculated from the colorimetric assays, using the factor for β-carotene, 0.6 mcg.=1 I.U. The fact that other workers have reported higher provitamin A activity for β-carotene in the rat bioassay indicates the dependence of the results on the particular conditions of the bioassay.The stability of vitamin A and β-carotene in commercially prepared margarines stored at 40°F. and 75°F. was studied by accepted colorimetric procedures. Average retention values of 94% or better were obtained in margarines stored two months when the vitamin activity was supplied either from β-carotene or from vitamin A.

The effect of subclinigal infections with Eimeria praecox and Eimeria tenella on pigmentation and vitamin a absorption in broilers

Synopsis Broilers were fed for the first 5 weeks on a starter ration containing 20 g of xanthophylls/ton. They were then divided into uniform groups and fed on either a broiler finisher ration supplying 30 g xanthophylls/ton or one supplying 20 g xanthophylls/ton and supplemented with 2.5 g canthaxanthin/ton. Six groups from each dietary regime were given 10,000 sporulated oocysts of E. praecox, daily for 5 d, six with 5000 sporulated oocysts of E. tenella daily for 5 d while the remaining six groups served as uninfected controls. All birds were housed in cages with solid floors to aid in recycling the infections over the 3‐week test period. The resulting subclinical E. praecox and E. tenella infections, regardless of dietary treatment, caused slightly reduced weight gains and slightly impaired food conversions. Shank and breast skin visual scores, plasma and toe‐web carotenoids and liver vitamin A levels were not depressed as a result of either coccidial infection.

Laboratory model for the detection of poultry growth promotants

Synopsis A laboratory model is described which allows the effective screening for compounds possessing antibacterial activity to increase growth and improve the conversion of food in poultry. The model utilises birds from 1 to 4 d of age with the supplements fed for 14 to 11 d, respectively, at 50 mg/kg in a high energy, commercial‐type broiler starter ration. The antibiotics tested and found active in the screening test include penicillin, penicillin and streptomycin, zinc bacitracin, chlortetracycline, erythromycin, lincomycin, bambermycins (moenomycin), neomycin, novobiocin, fosfomycin and thiopeptin. The non‐antibiotic anti‐bacterial, nitrovin, was also effective. Diethyl‐stilbestrol, melengestrol acetate, zeranol and reserpine were inactive. Thus, the screening procedure is responsive to compounds possessing antibacterial activity but not to compounds with hormonal anabolic activity or tranquilising‐sedative activity. The test also reflects the effects of “ clean ” and “ new ” quarters by increased g...

A critique of biological activity of L-lyxoflavin.

Summary Lyxoflavin has been shown to possess a limited ability to replace riboflavin in the nutrition of L. casei and the rat. In chicks, large doses of lyxoflavin produce small weight gains, which, however, can be matched by equal doses of riboflavin. The present evidence does not warrant the classification of lyxoflavin as a new vitamin.

Effect of roxarsone and canthaxanthin on broiler pigmentation

Synopsis Broiler chicks were fed on a commercial‐type ration containing 20 g oxy‐carotenoids/ton for 5 weeks, half receiving 0.005% roxarsone. All birds were then fed on finisher rations containing a moderate (20 g/ton) to high level (40 g/ton) of oxycarotenoids from food ingredients alone and in combination with 2 and 4 g canthaxanthin/ton for 26 d. The birds given roxarsone in the starter ration also received 0.005% roxarsone in the finisher ration together with the above‐listed oxycarotenoid supplements. Roxarsone was withdrawn from the ration 5 d prior to termination of the study to simulate commercial requirements. The continuous feeding of 0.005% roxarsone had no effect on weight gain, food conversion or pigmentation as assessed by visual shank scores, using the Roche Yolk Color Fan, and colorimetric assay of total carotenoid concentrations in plasma, toe‐web skin and shank skin. Shank visual scores reflected the increased levels of oxycarotenoids derived from food ingredients alone and the effect o...