Response of large white turkeys to virginiamycin from day-old to slaughter.

Diets containing 0 or 22 mg of virginiamycin per kilogram were fed to 448 Nicholas Large White turkeys from day-old to slaughter at 16 (females) or 20 wk of age (males). Weight gain of males, but not females, fed treated diets increased significantly from 0 to 4 and 4 to 8 wk of age, but not in later periods. However, final weights of both sexes were increased by treatment with virginiamycin. Feed efficiency of treated birds increased to 8 wk of age but not overall. Mortality and carcass finish and fleshing scores were unaffected by the antibiotic treatment.

Effect of bambermycins (Flavomycin) in diets for growing turkeys.

Two experiments were conducted to investigate the response of turkeys to graded levels of bambermycins++ in wheat-based diets. In one, 960 Medium White poults were fed 0,2,3, or 4 mg bambermycins per kg from day-old to 12 wk of age. In the other, 264 male and 408 female Large White poults were fed 0,2,5, or 10 mg bambermycins per kg from day-old to 15 (females) or 18 (males) wk of age. Response of Medium White poults increased with age, with significantly greater weight gain from 8 to 12 wk of age as well as final weights when the diet was supplemented with bambermycins. Large White poults responded with highly significant increases in gains from 0 to 4 and 4 to 8 wk of age, and a highly significant linear response to bambermycins in final weights. Although feed efficiency of Large White poults from 0 to 4 wk of age increased with bambermycins, overall efficiency in both trials decreased when the diets were supplemented. The earlier and greater response of Large White poults in comparison with birds of a Medium White strain may be related to the differing growth characteristics of those strains. The difference may also be related to the re-use of litter in the former trial. However, the effect of neither strain nor litter was determined within the same experiment.

Virginiamycin and monensin, alone or in combination, in turkey broiler diets.

Diets supplemented with either 22 mg of virginiamycin per kg, 99 mg monensin sodium per kg, or both, were fed to 960 Hybrid-1500 Medium White poults from day-old to slaughter at 12 wk of age. Weight gains from 0 to 12 wk were greater when the diet was supplemented with virginiamycin, alone or in combination with monensin (P less than .05). However, the combination of virginiamycin with monensin resulted in superior overall feed efficiency to that obtained with either additive alone.

Beta-carotene supplementation of turkey diets varying in fat and retinol.

1. The effects of supplementary beta-carotene (BC) at 0, 1.5, 15, 150, 1500 or 15,000 mg/kg diet on performance, incidence of leg problems, tibia ash, and plasma and liver concentration of BC and retinol of poults to 4 weeks of age were studied. 2. Body weight and food intake increased with dietary BC supplementation. Incidence of leg problems was not affected but tibia ash increased with BC supplementation. Plasma and liver BC and liver retinol increased with dietary BC but plasma retinol was not affected. 3. The effects of 0, 1.5, 15 or 150 mg BC/kg in diets containing either 30 or 60 g added fat/kg and either 1.2 or 12.0 mg retinol/kg on the above properties were studied in poults to 4 weeks of age. 4. Performance was not significantly affected by dietary fat. Efficiency of utilisation of food was depressed by the higher concentration of retinol. At 3 weeks of age birds given BC had fewer leg problems and higher tibia ash values than the control birds. Liver BC and retinol and plasma BC concentration increased with dietary BC. By 4 weeks, plasma and liver BC was higher and liver retinol was lower for birds given 1.2 compared with those given 12.0 mg/kg of retinol.

Effects of supplementary vitamin D3 on egg production of two strains of Japanese quail and growth of their progeny.

Two strains (University of Saskatchewan, white egg and wild type) of mature Japanese quail (Coturnix coturnix japonica), following a 4-week depletion period, were fed one of four diets varying in supplementary vitamin D3: a) no supplementary vitamin D3, b) National Research Council (NRC, 1977) recommended level of 1,200 IU vitamin D3/kg feed, c) 10 times, NRC levels, and d) 100 times NRC levels for 4 weeks. Egg production, egg weight, number of softshelled eggs, body weight, and feed consumption were not affected by vitamin D3 treatment. Hatchability of the white egg strain was not affected by vitamin D3 treatment. Hatchability in the wild type strain was reduced in those birds consuming diets unsupplemented with vitamin D3 although not significantly. Tibia ash was not affected by vitamin D3 treatment. Progeny from hens receiving no supplemental vitamin D3 were smaller throughout a 5-week growth period; however, feed consumption and percentage tibia ash content were similar to those of progeny from the other treatments. Progeny fed 480 IU vitamin D3/kg feed were larger, had higher tibia ash, and similar feed consumption compared with those fed a diet with no added vitamin D3.

Effects of vitamin D3, calcium, and phosphorus on growth and bone development of market turkeys.

A study was undertaken to determine the effects of maternal and poult nutrition on poult growth and bone development through to market age. Nicholas Large White turkey hens (200) were fed diets with 300, 900, or 2700 IU vitamin D3/kg from day-old to 37 weeks of age. Male poults (649 from Hatch 1 and 555 from Hatch 2) were fed diets containing .6 or 1.2% Ca; .4 or .8% available P; and 300, 900, or 2700 IU vitamin D3/kg to 4 weeks (Hatch 1) or 2 weeks of age (Hatch 2) in a complete factorial design. All Hatch 2 poults were given a "therapeutic" diet from 2 to 4 weeks, followed by normal grower diets from 4 to 24 weeks of age. Increasing the level of vitamin D3 in the hen diet increased weight at hatching and at 2 and 4 weeks, decreased mortality from 0 to 2 weeks, and increased bone ash percent and breaking strength and decreased the severity of rickets score at 2 weeks. Increasing the levels of Ca, P, and vitamin D3 in the poult diet gave reduced mortality from 0 to 2 weeks, increased weight at 2 and 4 weeks, increased bone ash percent and breaking strength, and decreased severity of rickets score at 2 and 4 weeks. Carcass fleshing score at 24 weeks was improved with 1.2% Ca. Conformation score and percent grade A carcasses increased linearly with level of vitamin D3 in the starter diet and were also improved by increasing the vitamin D3 in the breeder diet.

Effect of varying levels of dietary vitamin D3 on turkey hen egg production, fertility and hatchability, embryo mortality and incidence of embryo beak malformations.

Two hundred Large White turkey hens were fed diets varying in vitamin D3 supplementation (300, 900, or 2700 IU/kg feed) from day-old to 37 weeks of age. Hens receiving 300 IU vitamin D3/kg feed produced fewer eggs, which were lighter in weight and had thinner shells than those laid by hens receiving the higher levels of vitamin D3. Fertility was not affected by treatment; however, hatchability of eggs from hens fed 300 IU vitamin D3/kg feed was reduced by 48% from that of hens fed the two higher levels. A shortened upper mandible, which was detected in embryos during Week 4 of incubation, accounted for approximately 10% of the total embryo mortality and 49.5% of the embryo mortality, during Week 4. It appeared that hens fed the low vitamin D3 did not have adequate amounts of the vitamin to transport to the egg for normal embryonic development.

Influence of maternal vitamin D3 carry-over on kidney 25-hydroxyvitamin D3-1-hydroxylase activity of poults.

The effects of maternal vitamin D3 carry-over to the poult and dietary vitamin D3 on kidney 25-hydroxyvitamin D3-1-hydroxylase (1-hydroxylase) (EC 1.14.13.13) activity were studied in poults from 6 days prehatching to 46 days of age. Large White female turkeys from day-old were fed diets with either 300, 900, or 2700 IU vitamin D3/kg feed. Progeny from each maternal group were fed diets with either 0, 300, 900, or 2700 IU vitamin D3/kg feed. Low maternal vitamin D3 carry-over increased kidney 1-hydroxylase activity in embryos and poults to at least 5 days of age. Low dietary vitamin D3 increased the enzyme activity over that of poults fed higher levels. Kidney 1-hydroxylase activity peaked at about 8 to 18 days to a level similar in all groups. This peak is coincident with the appearance of rickets often noted in the field. Maternal diet did not affect plasma calcium (Ca) but plasma inorganic phosphorus (Pi) decreased with decreasing maternal vitamin D3 up to 14 days of age. Plasma Ca increased at 14 days with higher dietary vitamin D3, as did plasma Pi from day 8. Plasma alkaline phosphatase increased with age to 18 days and then declined. Tibia ash increased with higher maternal vitamin D3 carry-over to 12 days and with higher dietary vitamin D3 after 12 days of age. Body weight was reduced with low maternal vitamin D3 carry-over until at least 2 weeks of age, after which the effect of progeny diet was highly significant; birds receiving 2700 IU vitamin D3/kg feed were almost twice as large as those receiving none. This study shows the importance of adequate maternal carry-over of vitamin D3 and its possible influence on the development of rickets in starting poults.

Dietary level of fat, calcium, and vitamins A and D3 as contributory factors to rickets in poults.

Two experiments were conducted on dietary predisposition to rickets in poults. The first experiment compared fat type (corn oil or tallow), level of added fat (3.5 or 7%), vitamin D3 (900 or 2,400 IU/kg feed), and total calcium (.6, 1.2, or 3%) inclusion in the diet. Poults fed diets supplemented with corn oil had higher percentage tibia ash than poults fed tallow-supplemented diets. Vitamin D3 included at 2,400 IU/kg feed increased body weights significantly by 2 and 4 weeks of age and lowered plasma alkaline phosphatase (AP) at 2 and 4 weeks compared with diets containing 900 IU/kg feed. Tibia ash was significantly greater with the higher vitamin D3 supplementation at 2 weeks. At 2 weeks of age both low (.6%) and high (3%) levels of dietary calcium increased plasma AP, decreased tibia ash, and decreased body weight compared with diets containing 1.2% calcium. By 4 weeks of age, diets containing 1.2 and 3% calcium had no significant effects on body weight and plasma AP; however, tibia ash was significantly greater with these levels than with the .6% calcium diets. The second experiment compared level of dietary tallow inclusion (2.5 or 7%) and supplementary vitamin A (4,000, 16,000, or 44,000 IU/kg feed). The high tallow diets decreased tibia ash at 3 weeks, and the maximum supplementation of vitamin A significantly depressed body weight. Clinical rickets were first noted at 18 days of age. By 26 days of age the higher level of dietary fat and the highest level of vitamin A caused a significant increase in severity of rickets. The results suggested that rickets can be induced by high dietary levels of tallow and vitamin A.

Nutrient deficiencies in broiler chicks: a demonstration project for undergraduate students.

A demonstration project is described that proved to be popular with undergraduate students enrolled in a senior level course on animal and poultry nutrition. A total of 100 male, day-old broiler chicks were housed in a Petersime battery brooder and used in a 3-week test. Students were responsible for the management and care of the birds throughout the test. The birds were allotted to 5 groups (4 replicates each of 5 birds per group) and the test involved the omission of calcium, phosphorus, vitamin D3, or sodium chloride from a nutritionally adequate diet for a period of 2 weeks. After that period, one pen of each group was repleted with the control diet. Feed consumption, liveweight, feed conversion efficiency, and tibia bone ash content were measured weekly. Deficiency signs of the nutrients were observed, and it was noted that sodium chloride had the most marked effect on growth. Phosphorus deficiency had the most severe effect on bone development and resulted in a high incidence of rickets. Repletion resulted in a marked response in all parameters measured and was most marked in the group deficient in sodium chloride.