ABSTRACT: In this paper, the detection of type I collagen degradation during the softening phenomenon of yellowtail muscle, was examined. Acid soluble collagen was isolated from dorsal ordinary muscle at death and after 24-h chilled storage. In the abundant ratio of subunit components, an increase in β12 chain (5.4 points) and a decrease in components with molecular weights larger than γ chain (7.0 points) after 24-h chilled storage, was found. Type I collagen was detected in the alkali-soluble fraction by SDS-PAGE. Its amount calculated from hydroxyproline contents in alkali-soluble fraction was increased from 0.097 mg/g muscle to 0.155 mg/g muscle during 24-h storage. The increased alkali-soluble collagen (0.058 mg/g muscle) was about 1.4% of whole collagen. These results suggest that a slight decomposition of type I collagen of yellowtail muscle may occur and subsequently becomes alkali-soluble corresponding to postmortem softening. 相似文献
Ontogenetic changes in digestive tract histology and digestive enzyme histochemistry were investigated 11 to 36 days post-hatch in white sturgeon Acipenser transmontanus larvae. From initiation of exogenous feeding (12 days post-hatch), larvae were fed a commercial salmonid diet for the ensuing 24 days. The digestive system of white sturgeon displayed a high degree of morphologic organization and functionality at the onset of exogenous feeding. An enhancement of digestive capacities occurred with transition to active feeding. On day 2 of feeding, there was a clear increase of alkaline phosphatase, aminopeptidase M, dipeptidyl peptidase IV, and -glutamyl transpeptidase activity in the brush border of the spiral intestine. This strong activity is an apparent confirmation of the importance of this segment of the intestine for protein digestion and nutrient absorption. The functional development of the pyloric intestine occurred on day 4 and was concomitant with an increase in the activity of brush border and cytoplasmic enzymes such as acetylcholinesterase, dipeptidyl peptidase II, - and -galactosidases. The absence of acetylcholinesterase, lactase, nonspecific esterase, and weak activity of exopeptidases and alkaline phosphatase in the anterior intestine suggests that this segment of the intestine may be less important in nutrient absorption than the pyloric and spiral intestines. The observed quantitative and qualitative differences in enzyme activity along the intestine indicate a high degree of specialization of each segment for specific digestive and absorptive processes. 相似文献
Three approximately isoenergetic (17 kJ g?1) diets were formulated with dietary protein levels of 270, 360 and 480 g kg?1 (DM basis) providing protein-to-energy ratios of 15.69, 20.48 and 27.16 mg crude protein (CP) kJ?1, respectively. The effects of these diets on several growth and nutritional parameters were evaluated for the fry (2.50 ± 0.184 g) and fingerlings (11.53 ± 0.023 g) of Siganus canaliculatus (Park). Maximum growth and best feed utilization efficiency of fry were obtained using the diet containing 480 g kg?1 protein and P:E ratio of 27.16 mg CP kJ?1. For fingerlings the best results were obtained with the diet containing 360 g kg?1 protein and P:E ratio of 20.48 mg CP kJ. Body composition of the fry was not affected by the feeding regime whilst the effect was evident in the fingerling groups. The carcass protein content of the fingerling was observed to increase with increasing P:E ratios while lipid content decreased as P:E increased. 相似文献
A rapid extraction procedure and a HPLC method for quantitative measurements of the concentration of rotenone in oysters (Ostrea edulis) and in seawater is presented. The absorption rate of rotenone by oysters was rapid. With an average rotenone concentration in the seawater of 26 ppb, the concentration in the oysters reached 4.6 ppm after 4 days of exposure. The t1/2 of the excretion of rotenone was 40 h at 10°C. The absorption rate was highly affected by both the rotenone concentration in the seawater and the seawater temperature. Rotenone was quite stable in seawater at low temperatures. At an average temperature close to 0°C, 18% of the rotenone added was still present 45 days after preparing the solution (1 ppm Gullviks rotenone mixture) in seawater. The acute mortality observed was closely related to the measured concentration of rotenone in the oysters. 相似文献
Abstract. Thrombosis of minute vessels is a common feature of acute furunculosis in Atlantic salmon. Crude extracellular products (F.CP) of Aeromans, salmonicida injected into the dorsal aorta of cannulated fish elicited an activation of the coagulations systems of the fish When screened with a number of chromogenic substrates, the ECP protease revealed a factor-X like activity. Thus, it may he hypothesized that the ECP induces thrombosis by entering the fish coagulation systems at factor X. and that thrombus formation is a way of creating a site of infection. 相似文献
The distribution of immunoreactive GnRH was studied in the brain and pituitary gland of normal and human chorionic gonadotrophin (hCG) injected silver eels. It was found that the general organization of GnRH systems in this species is similar to that reported in other teleosts. Cell bodies were present in the olfactory bulbs, ventral telencephalon, periventricular hypothalamus and dorsal tegmentum. No positive perikarya could be detected in the preoptic region. Only scarce fibers were observed in the proximal neurohypophysis. Treatment with hCG does not modify the distribution of GnRH but it increases the density of positive structures, in particular at the level of the pituitary. The results are discussed in relation with the present status of knowledge of the mechanisms underlying the blockage of sexual maturation in the European eel at the silver stage. 相似文献
The farmed red-bellied pacu Piaractus brachypomus is a valuative commercial fish widely exploited in fish farming. Histopathologic alterations in small intestine of this fish were associated with heavy roundworms infection. Of a total of thirty-five fish examined, all were parasitized with a prevalence of 100%, intensity of 290–6403, and mean intensity of infection of 4467.5 parasites per fish. According to the morphological features of whole nematodes examined using light and electronic microscopy, the parasite was identified as Rondonia rondoni Travassos. Rev Vet e Zoot 10, 59–70; 1920. The fish intestinal tissue alterations include fusion of villi, edema, disorganization of epithelial cells, epithelial abrasion, and flaking of the villus at mucosa layer level and submucosa layer with some regions of necrosis and lymphocyte infiltrate. This is the first report of histopathological alterations caused by infection of the atractid nematode R. rondoni in a farmed population of P. brachypomus in the Peruvian Amazon. The study points out the need of improving the strategies of parasitic prevention and control in order to better prevent future disease outbreaks.
Ovaries and testes from the Russian sturgeon at different stages of sexual maturity were incubated with ;sup3;H-androstenedione or 3H-pregnenolone. The major metabolites of androstenedione in both sexes were testosterone and 5- and 5ß-androstanediols, but no evidence was found for the gonadal production of 11-oxygenated androgens. Pregnenolone was converted to 17-hydroxyprogesterone, androstenedione and testosterone together with reduced metabolites. 11-Oxygenated androgens were found in female serum by gas chromatography-mass spectrometry (GC-MS), in serum of both sexes by radioimmunoassay (RIA), and was detectable by RIA in interrenal but not gonadal tissue. The results suggest that sturgeon may differ from teleosts in that 11-oxygenation may take place in extragonadal tissues. 相似文献