Seasonal variations of thyroid hormone levels in wild fish.

Variations in plasma thyroxine (T4) and triiodothyronine (T3) contents of pike, pikeperch, perch, bream and chub from a large reservoir (Pareloup, South of France) were investigated before and during the progressive emptying of the reservoir. Fish were caught by gill nets, except at the last time of emptying when controls were collected with landing nets. Both iodothyronine levels showed desynchronized seasonal cycles resulting in higher T3/T4 ratios in fish stressed by gill-netting in early summer. The aforementioned results principally emphasized the prevailing influence of the technique of catching on eliciting stress responses and subsequent thyroidal impairment in all five species. However, the much higher amounts of T4 and/or T3 observed in specimens caught in the later stages of draining gave evidence to suggest that the progressive alteration in habitat might also have indirectly affected the thyroidal status of these fish, this latter result leading to the consideration of fish plasma thyroid hormones as possible endocrine biomarkers of chronic perturbation.

[Nutritive value of white lupin (Lupinus albus var Lutop) in rainbow trout (Oncorhynchus mykiss). Effect of extrusion cooking]. / Valeur alimentaire du lupin blanc (Lupinus albus var Lutop) chez la truite arc-en-ciel (Oncorhynchus mykiss). Effet de la cuisson-extrusion.

Two experiments were conducted in rainbow trout (Oncorhynchus mykiss) to assess the nutritional value of diets containing crude (LC) or extruded at 120 degrees C (LE1) and 145 degrees C (LE2) lupin var "Lutop" as a partial protein source. In the first experiment, the apparent digestibility coefficient (ADC) of diets with 20 and 30% lupin was measured. In a second trial, the effects of diet containing 20% crude and extruded lupin on growth performance of trout were analyzed. It was found that the ADC of dry matter, proteins and lipids decreased with the incorporation of 20% crude lupin. The extrusion-cooking process increased the digestive utilization of nutrients, especially the nitrogen-free extract. After 83 d of feeding, decreased growth performance was observed in trout fed on LC diet. Those fed diets LE1 or LE2 showed increased growth, food intake, food efficiency and protein retention, attributed to the disappearance of antinutritional factors in extruded lupin.

Cerebrospinal fluid analysis and clinical outcome of eight dogs with eosinophilic meningoencephalomyelitis.

Eight dogs, 14 weeks to 5.5 years of age, had signs of diffuse or multifocal meningoencephalomyelitis. The total white cell counts of the cerebrospinal fluid (CSF) ranged from 11 to 5,550 cells/microliters; the percentage of eosinophils ranged from 21% to 98%. The total CSF protein content range was 19 to 1,430 mg/dl. On necropsy, two dogs had granulomatous encephalomyelitis due to protozoan infection. The other six dogs, of which three were Golden Retriever dogs, appeared to have an idiopathic eosinophilic meningoencephalitis; four of these dogs recovered. The significance of eosinophils in CSF and the possible emergence of a new encephalitic syndrome of dogs involving a hypersensitivity to an unknown agent is also discussed.

Responses to prolonged hypoxia by rainbow trout (Salmo gairdneri) I. Free amino acids and proteins in plasma, liver and white muscle.

In order to estimate the mobilization of nitrogen compounds for energetic purposes in trout under hypoxic conditions, commercial-size rainbow trout, acclimated to 15°C, were maintained for 10 weeks at an oxygen level of 5.3 ± 0.5 mg/l ('hypoxic' group) or 8.4 ± 0.4 mg/I (control group), and the changes in tissue concentrations of free amino acids and proteins studied. In animals subjected to hypoxia, there was a decrease in plasma free amino acids involved in gluconeogenesis, liver alanine and aspartic acid, plasma and liver protein concentrations, and muscle free histidine. These results suggest a trend of rainbow trout metabolic activity towards energy production at the expense of anabolism when oxygen availability in water is limited over a long period of time.

[Effect of temperature increase on some aspects of nitrogen catabolism in rainbow trout (Salmo gairdneri Rich.)]. / Influence d'une augmentation de la température sur certains aspects du catabolisme azoté chez la truite arc-en-ciel (Salmo gairdneri Rich.).

Rainbow trout acclimatized to 9 degrees C were subjected to a temperature increase (up to 17 degrees C) for 16 hrs. During the period of acclimatization to 17 degrees C, we studied blood ammonia and urea and the hepatic activity of glutamate dehydrogenase, glutaminase, uricase and arginase. The daily mean rates of blood ammonia and urea did not differ significantly at 9 and 17 degrees C. However, the pattern of these two parameters during the circadian cycle was not the same at 9 degrees C as after 23 days at 17 degrees C. The enzymatic activities rose after one day at 17 degrees C and remained unchanged, except for arginase which showed perfect thermal compensation. During the circadian cycle, there was some similitude between glutaminase activity and blood ammonia at 9 degrees C and after 23 days at 17 degrees C, as well as between arginase activity and blood urea.

[Effect of two rearing conditions on growth and body composition in carp (Cyprinus carpio L) (author's transl)]. / Influence de deux modes d'élevage sur la croissance et la composition corporelle de la carpe commune (Cyprinus carpio L)

A comparative study was made of the growth and of the influence of seasonal changes on nitrogen and carbohydrate metabolism of carp kept in batches in natural ponds. 10 Growth is active only in natural ponds. In batches where only industrial dried foods are used, no growth can be measured. 20 Activity of ribonucleic and protein metabolism is correlated with seasonal variations of water temperature in both conditions.