Inv(1) allotype: effect of immunoglobulin G heavy chain subtype on its expression

More protein is required to detect the Inv(1) antigen carried in the light chain of immunoglobulin G molecules when the light chain is combined with a gamma2 heavy chain than when it is combined with a gamma1 or gamma3 heavy chain. One of the four gamma2 heavy chains used in the experiment, however, was as efficient as the gamma1 and gamma3 chains, indicating that there may be two subtypes of gamma2. Inv(1) was more easily detected in one of the two light chains used in the experiment. This difference may be associated with the subtypes of the kappa chain derived from studies of the variable portion of the chain.     

Haematology of subclinical fatty liver in dairy cows

The relationship between liver fat content and haematology was investigated in 369 cows from eight herds sampled in the second week after calving. High levels of fat in the liver were associated with a depression in total white cell count and in neutrophils, eosinophils and lymphocytes. There was no correlation between liver fat content and the percentage of E rosetting lymphocytes, packed cell volume or haemoglobin concentration. The changes in peripheral white cell counts may be related to the increased incidence of post parturient disease in cows with fatty liver.     

Effect of graded nitrogen supplements on egg protein synthesis and body protein retention in broiler hens

In the top laying period (29th/30th week of life) egg protein synthesis and protein retention in the bodies of laying hens were ascertained. Based on egg-N analyses, the relation between N-intake/live weight0.67kg and egg-N discharge/kg LW0.67kg was regressively calculated and described. The subtraction of egg-N discharge/LW0.67kg from N-balance/LW0.67kg made it possible to estimate N-retention/LW0.67kg in the body. From the intersection of this curve with the chi-axis it follows that the broiler hen meets the N-requirement for maintenance and egg production with a daily consumption of 1,264.7 mg N/LW0.67kg, which corresponds to 15.8 g crude protein, and then neither loses nor retains body protein. At a daily intake of this amount of CP (15.8 g) the broiler hen produces 44.1 g egg per day. An energy intake of more than 70 EFUhen/animal and day resulted in fat retention in the broiler hen.     

Induction of prolonged larval feeding stage by juvenile hormone analogues inTribolium Castaneum

Dietary ZR-512 and ZR-619 at concentrations of 10 — 1000 ppm induced prolongation of the larval feeding period up to tenfold, increasing larval weight up to double that of untreated larvae. A comparison study of four juvenoids, using 200 ppm of ZR-512, ZR-515, ZR-619 or ZR-777, showed that ZR-515 elicits the highest larval weight (6.2 mg) and ZR-777 the lowest (3.6 mg). In all cases a pronounced enhancement of larval weight — of 50 — 250% relative to untreated larvae (2.4 mg) — was obtained.Tr. castaneum larvae reared up to their 3rd instars on a diet containing 100 ppm of ZR-512, ZR-515, ZR-619 or ZR-777 and then transferred to a juvenile hormone-free diet, were not affected. The period between 4th instar larva and pupation should therefore be considered as critical for juvenile hormone effect. The induced prolongation of the larval stage after juvenile hormone treatment was followed by a pronounced enhancement of cuticle phenoloxidase activity, indicating an alteration of the larval biochemical processes. Although juvenile hormone treatment inhibitsTr. castaneum pupation and emergence, it markedly prolongs larval feeding stage and weight and thus accelerates damage.     

Extracorporeal perfusion of the sheep rumen]

We constructed a modified perfusion apparatus and elaborated a method of extracorporal perfusion of the rumen of sheep. As perfusates we used the bovine plasma diluted in a ratio of 1:1 of an isotonic sodium chloride (NaCl) solution and the whole autologous blood. Transaminases GOT and GPT, ammonia and pH were determined in the perfusate. The different perfusions were evaluated according to previously determined perfusion conditions and criteria. A subject for discussion is the question of suitability of the parameters under examination for judging the state of the perfused organ. The described method is suitable for the study of metabolical processes in the rumen wal.