Effect of age and sex on the eviscerated yield,muscle and edible offal of a commercial broiler strain

1. Comparisons of the effects of age (up to 364 d) and sex on the rate of growth, eviscerated yield, blood loss and yield of skin, breast, thigh and drumstick muscles, heart, liver and gizzard have been made on a commercial British broiler strain.

2. Male broilers grew linearly up to 76 d whereas the females grew more slowly after 35 d. At 364 d the difference in live body weight was small.

3. Up to 56 d, males had a slightly higher eviscerated yield. There was no significant difference between the sexes beyond this age.

4. The proportional yield of breast muscle was variable with age, whereas that of thigh and drumstick increased with age in the male, particularly at 175 and 364 d.

5. After 35 d the proportion of skin was larger in females, whereas the gizzard as a proportion of live body weight in both sexes decreased rapidly between 21 and 76 d. Blood loss during killing was always higher in male broilers after 21 d.     

Chronic subclinical ovine fascioliasis: plasma glutamate dehydrogenase, gamma-glutamyl transpeptidase and aspartate aminotransferase activities and their significance as diagnostic aids

The effect of low grade chronic Fasciola hepatica infection on the concentration of plasma glutamate dehydrogenase (GD), gamma-glutamyl transpeptidase (gamma-GT) and aspartate aminotransferase (AST) was investigated in sheep dosed daily with three (AL3), eight (AL8) or 14 (AL14) metacercariae over 22 weeks or given a single dose of 200 metacercariae. Significant increases in plasma GD activity first occurred after nine, 12 and 23 weeks and in gamma-GT activity after 12, 24 and 32 weeks for groups AL14, AL8 and AL3 respectively. Changes in AST activity were not as clearly related to dose level. In sheep with single infection, both GD and gamma-GT were capable of detecting liver damage resulting from the migration of 10 or more flukes. Plasma GD and gamma-GT activities are more sensitive indicators of liver cell damage in chronic subclinical fascioliasis than AST activity and gamma-GT may be more suitable as a diagnostic aid on account of its greater stability.     

Skin blackening during the cooking of spent laying fowls

1. Blackening of the skin in factory processed cooked hens has been associated with elevated copper levels.

2. The degree of blackening was not directly related to copper content although the latter level was always higher than in control hens.

3. Simulated factory procedures, using scald water at 53 °C or 60 °C containing 50 mg Cu²⁺/1 and 50 mg C1₂/1, produced blackened skins of varying intensity on cooking.

4. It is suggested that the problem arose from a malfunction of the chlorination plant which produced excessive levels of chlorine and low pH, followed by erosion of copper from water pipes and subsequent interaction of copper and chlorine with the chicken skin.     

A study of liver function in rats with mirex-induced enlarged livers

The functional capacity of a mirex-induced, enlarged liver was studied in rats. The tests used were sulfobromophthalein clearance, hepatic cytochrome P-450 concentration, serum total protein concentration and electrophoretic pattern, serum total lipid concentration, serum glucose concentration, and the liver response to epinephrine. There was no indication of a loss of functional capacity in the enlarged liver. Sulfobromophthalein clearance and microsomal cytochrome P-450 concentration indicated an increase in total liver functional capacity. We conclude that mirex is not a direct hepatotoxin producing generalized parenchymal cell damage.     

Factors affecting the development of disease symptoms in potatoes infected by <Emphasis Type="Italic">Tobacco rattle virus</Emphasis>

Infection of potato plants with Tobacco rattle virus by its nematode vector can have different outcomes, including the development of spraing symptoms in progeny tubers. A novel syndrome described here comprises a generalized mottle in leaves on all stems, together with virtually total failure to produce daughter tubers. The outcome of infection depends partly on the potato genotype, but field trials with 15 varieties showed that the incidence and severity of spraing symptoms at three sites differed. There was no evidence that this was due to differences in virulence among the virus isolates at the sites, but it was probably the result of environmental differences that influenced the numbers and activity of the vector nematodes. At the most severely affected site, spraing symptoms were found in all varieties tested, except Record, including several that were not affected at the other two sites. Taking both severity and incidence of symptoms into account, the ranking of varieties was similar at each site. The incidence of spraing symptoms was greater in larger than in smaller tubers, and increased with later harvest dates, but did not increase when early harvested tubers were stored. Tobacco rattle viruswas detected in the roots of many of the weeds growing at one of the sites and in the roots of a few plants of the subsequent barley crop.