Amino acid interactions in chick nutrition. 4. Growth, food intake and plasma amino acid patterns

A series of experiments has been conducted with chicks to study the effects of excess lysine, leucine and incomplete mixtures of amino acids on growth, food intake and plasma amino acid patterns.

Excess lysine induced a marked depression in growth within 48 h. Towards the end of the experiment, the chicks lost weight and showed no signs of adaptation to the excess dose of lysine. The plasma concentration of arginine fell within 24 h of feeding excess lysine but the reduction in food intake did not occur until 6 d of the experiment had elapsed. Excess leucine similarly caused a rapid retardation of growth which was followed subsequently by a depression in food intake. Mixtures of amino acids lacking in leucine, isoleucine and valine also induced marked growth inhibitions the severity of which were enhanced by the inclusion of leucine and isoleucine in the mixtures. Growth tended to be adaptive in chicks fed on the incomplete amino acid mixtures but non‐adaptive in those fed on excess leucine.

Pair‐feeding studies indicated that appreciable differences in weight gain still occurred when food intake was equated between control groups and groups receiving excess lysine or leucine.

The results of the present study indicate that the depression in food intake cannot account completely for the ill‐effects of excess lysine and leucine. They also suggest that the adverse effects of lysine and leucine are distinct from those caused by incomplete mixtures of amino acids.     

FERTILE TILLER PRODUCTION AND SEED YIELD IN MEADOW FESCUE (FESTUCA PRATENSIS L.)

The seed-producing capacity of two varieties of meadow fescue, S215 and S53, sown at three different spacings, was compared. One level of nitrogen was applied on three different dates in the spring. Tiller counts were made periodically during the growth of the crop. Fertile-tiller production was found to be related to vegetative growth.
The varieties differed not only in yield, but also in growth dynamics. A larger percentage of overwintering shoots became fertile in the hay variety, than in the pasture variety.
Drill spacings had significant effects on plant establishment and on vegetative-and fertile-tiller numbers. In both years N applied in March gave the highest production of fertile tillers. Date of N application did not produce marked trends in yield. The influence of spacing and date of N application on the number and density of spikelets indicated that the plant adjusted itself to environmental factors. Thus spikelet numbers were reduced in early heads with narrower drill spacing and with late applications of N. Head emergence was earlier in narrow drills, but time of N application in the spring did not produce significant differences in this respect.     

Multiple ocular colobomas in the snow leopard (Uncia uncia)

Two singleton female snow leopard cubs are reported with bilateral central upper lid colobomas. In addition, one cub had a coloboma of the fundus in one eye extending from the lower optic disc region. Surgical treatment by wedge resection was successful in both cases. Details of ocular colobomas in other snow leopards reported in the literature are described and it is suggested that the exact etiology of the condition in this species may be discovered by further study of similar colobomas in the domestic cat.     

Reproductive response of ewes to immunization with Fecundin (ovandrotone)

Ewes of five crossbred genotypes (total of 221 ewes) were immunized with a commercial preparation of androstenedione-7HSA in DEAE dextran adjuvant in a 2-yr trial. In yr 1 ewes were allocated within genotype to a 2 x 2 application of immunization and premating flushing. In yr 2 they were allocated within previous Fecundin treatment into either Fecundin-treated or control groups. First-time immunization with Fecundin increased ovulation rate by .70 ova/ewe in yr 1 and by .85 ova/ewe in yr 2 (P less than .05). Ewes treated in both years produced fewer ova than those treated in the 2nd yr only (P less than .05), but they did not differ in litter size. Although Fecundin reduced conception to first mating, the overall conception rate was not affected. Litter size of treated ewes was increased by .19 and .38 lambs/ewe lambing (P less than .05) in yr 1 and yr 2, respectively. Fecundin treatment in yr 1 produced a carry-over effect in yr 2 by increasing litter size by .26 lamb/ewe (P less than .05) while reducing conception to first mating. The litter size of ewes with two ovulations was reduced by Fecundin treatment in yr 1 (P less than .05) but showed no consistent pattern in yr 2. Overall, ewes with two ovulations produced .7 to .8 more lambs than ewes with one ovulation, and ewes with three ovulations produced .4 more lambs than those with two ovulations. Ewes of different genotypes did not differ in their response to Fecundin.     

Effect of alpha-tocopheryl acetate supplementation on vitamin E concentrations in Greyhounds before and after a race.

OBJECTIVES: To determine effect of alpha-tocopherol supplementation on serum vitamin E concentrations in Greyhounds before and after a race. ANIMALS: 8 adult racing Greyhounds. PROCEDURE: Dogs were given 2 capsules of alpha-tocopheryl acetate (total, 680 units [0.5 g]) with food that contained < or = 15 mg of vitamin E/kg each morning for 7 days. Dogs were exercised in a 30 X 30-m grass paddock for 15 minutes twice a day and raced for 500 m twice a week. Blood samples were collected before and 5 minutes after a race, before supplementation was begun, and after 7 days of supplementation. Blood and diet samples were analyzed for tocopherols and alpha-tocopheryl acetate. RESULTS: Before supplementation, serum alpha-tocopherol concentration after racing (mean +/- SD, 6.7 +/- 2.4 mg/L ) was significantly lower than before racing (12.2 +/- 3.1 mg/L). After supplementation, alpha-tocopherol concentrations were significantly higher overall, although values obtained before (26.6 +/- 5.2 mg/L) and after (29.8 +/- 3.6 mg/L) racing were not significantly different. CONCLUSIONS AND CLINICAL RELEVANCE: Supplementation with alpha-tocopheryl acetate increased serum alpha-tocopherol concentrations and eliminated the decrease in alpha-tocopherol concentration that was detected after a race, which may decrease oxidation during exercise and improve performance or recovery.     

Cervical spondylomyelopathy ('wobbler' syndrome) in the dog: A study based on 224 cases

Over the past 10 to 12 years, cervical spondylomyelopathy has been increasingly recognised in large breed dogs. The breeds mainly affected are dobermanns, great danes and basset hounds. Factors such as age, sex and location of the lesions are discussed in detail based on findings from 224 cases seen at the University of Liverpool Small Animal Hospital. The anatomical changes responsible for the signs show some striking similarities in young dogs of all the breeds affected. Where the condition is commoner later in life, such as in the dobermann, the changes and their effect on the spinal cord show considerable differences. These different findings are compared, and an attempt made to explain them.