A feeding experiment was conducted to evaluate the efficacy of, and determine the requirements for dietary AsA (l-ascorbic acid) using its popular derivative l-ascorbyl-2-monophosphate-Mg (APM) for juvenile Pacific bluefin tuna (PBT). The five test diets (with APM-0, -400, -800, -1200 and -1600) were prepared by adding 0, 400, 800, 1200 and 1600 mg of APM kg diet?1, respectively. These diets, together with chopped sand lance (the control diet), were administered, in duplicate to 0.27 g PBT at 25 days after hatching (300 juveniles per 15 m3 tank). The PBT were fed to apparent satiety 6 times a day for 2 weeks. While final body weight, feed conversion and survival showed no differences among diets APM 400–1600, PBT fed APM-0 indicated lower growth performance together with anorexia, dark pigmentation and ataxia from 5 days and reached 80 % mortality at 12 days after the start of the feeding trial. In addition, liver and brain ascorbic acid (AsA) concentrations increased with increasing dietary APM levels, the values were similar in PBT fed diets with APM-1200 and APM-1600, and liver and brain concentrations of AsA were significantly higher in these fish than in the PBT fed the other diets (P < 0.05). The PBT responded to increasing dietary APM, and the fish fed APM-1200 had the highest weight gain, protein and lipid content. The data indicate that PBT can utilize APM as an AsA source and suggest that dietary supplementation with APM-1200 (454 mg AsA kg?1 diet) would result in satisfactory growth. 相似文献
Type I collagen is widely distributed in most organs in teleosts. It plays a role not only in intercellular adhesion, but also in molecular signaling. In this study, Pacific bluefin tuna (PBT) procollagen α1 (I) cDNA was cloned and characterized. The nine fragments of a procollagen α1 (I) chain cDNA clone were prepared and spliced together to create the complete coding region. The resulting amino acid sequence was homologous with that of other teleosts. The mRNA expression profile of PBT procollagen α1 (I) in various tissues and the phylogenetic analysis with other vertebrate procollagen α1 (I) chains suggest that PBT procollagen α1 (I) could be a precursor form of the PBT type I collagen α1 chain. In addition, its level of expression in PBT larvae and early juveniles gradually increased with somatic growth. This increase was related to the standard length, wet body weight, and protein content of each individual fish. Therefore, the expression profile of procollagen α1 (I) may be a useful indicator for somatic growth in fish larvae and juveniles. 相似文献
Taurine is often added to artificial fish diets to compensate for a reduction in fish meal (FM). However, the taurine content of FM‐based diets is typically lower than in diets consisting of raw fish, even in diets where FM is the only protein source. We evaluated the effects of dietary taurine in FM‐based diets on epidermal thickness and scale detachability in red sea bream Pagrus major. We compared the effect of diets containing 0% (control), 0.3% (Tau‐0.3%), 0.6% (Tau‐0.6%) and 1.0% (Tau‐1.0%) taurine. Red sea bream (average body weight, 39 g) were fed these diets for 7 weeks. Taurine supplementation had no effect on growth, feed intake, feeding efficiency, or survival. However, the epidermal thickness was higher in fish in the Tau‐0.6% and Tau‐1.0% groups than in the control and Tau‐0.3% groups. Similarly, scale loss was significantly higher in the control group than in the Tau‐0.6% and Tau‐1.0% groups. Our results suggest that supplementation with >0.6% taurine (1.0% in diet) improves skin condition. 相似文献
A 12-week laboratory incubation experiment was conducted to determine the effect of chemical composition of residues of nine plant species on their cumulative net nitrogen (N) mineralization in soil under submergence (SUB) and field capacity (FC) water conditions. The influence of residues and of water regimes on residue-N released over time was significant. Net mineralization was higher in FC than SUB especially in later periods, although differences either among soil water levels or among species were not significant in all the periods sampled. Net N release had significant correlations with initial N and ratios of carbon, lignin or polyphenol or the (lignin + polyphenol) to N concentration of residues under two water conditions. (Lignin + polyphenol):N ratio in SUB and carbon/nitrogen (C:N) ratio in FC showed highest correlations with N mineralization in all periods and explained 64.1% variation in N mineralization from residues under SUB and 64.5% under FC after 2 and 8 weeks, respectively. 相似文献
An investigation was carried out to study the antibiotic sensitivity of avian strains of Pasteurella multocida and to select an effective antimicrobial agent for control of avian pasteurellosis in India. A total of 123 strains of P. multocida recently isolated from different avian species (chicken, duck, turkey, quail, and goose), from different regions of India were subjected to antibiotic sensitivity tests using 20 different antibiotics. Absolute resistance was observed against sulfadiazine. The studies indicated that the strains were most sensitive to chloramphenicol (73.98%), followed by enrofloxacin (71.54%), lincomycin (64.23%), norfloxacin (61.79%) and doxycycline-HCl (56.91%). The majority of the strains were found to exhibit intermediate sensitivity. Chloramphenicol was selected and suggested for treatment. Antibiogram studies also revealed the emergence of multidrug-resistant strains of P. multocida among Indian poultry. 相似文献
From March 2007 to March 2009 we quantified plant diversity at Chilapatta Reserve Forest in Terai Duars in the Indian eastern Himala-yas. We sampled stratified random nested quadrats. Species richness was 311, representing 167 genera and 81 families. The species diversity index and concentration of dominance of the forest were 2.20 and 0.0072, respectively. Shannon-Wiener index and evenness indices were 4.77 and 1.44, respectively. The Importance Value Index (IVI) of species ranged from 0.13 to 37.94. The estimated diversity indices indicated heterogene-ity of the forest in its composition, structure, function and dynamics. Rich forest plant diversity supports the need for continued conservation of tropical forests. 相似文献
The present study aims to assess the impact of improved management practices on productivity, profit, and consumption expenditure of carp farmers. This study was carried out in three of Bangladesh’s top carp-producing districts (administrative units). A total of 300 carp farmers were surveyed through face-to-face interviews. Data were analyzed with propensity score matching (PSM), inverse probability weighting (IPW), and inverse probability weighted regression adjustment (IPWRA). Improved management practices, such as improved fingerling variety, stocking density, feeding, pond water change, lime application, and proper drainage facilities, were considered to achieve the study’s objectives. Improved management practices were classified into simple, intermediate, and complex practices based on their complexity. Adopters of improved management practices achieved significantly higher productivity (248–299 kg ha?1) based on various matching techniques compared to non-adopters. The impact of adoption on profitability and consumption expenditure was 22% and 34% on the basis of IPW. Due to higher productivity and profit, adopters were able to spend more on consumption. Findings also revealed that adopting simple management practice is insufficient to boost productivity and profit. More research is needed to develop and optimize the improved management practices as a package. Improvement in extension services is suggested to improve the adoption.
Black soldier fly meal (BM) is an outstanding candidate as a fish meal (FM) substitute because it contains relatively high protein and essential amino acids. In this study, we replaced FM in red sea bream diets (Pagrus major) with BM to investigate its effect on growth and feed utilization. Six isonitrogenous and isolipidic experimental diets were prepared by substituting 0%, 20%, 40%, 60%, 80% and 100% FM protein with BM (Control, BM20, BM40, BM60, BM80 and BM100, respectively). After the 8-week feeding trial, final body weight, weight gain, specific growth rate and feed efficiency decreased linearly with increasing dietary BM level (p < 0.05). Apparent digestibility of protein and fat and serum total cholesterol concentration decreased with increasing dietary BM levels (p < 0.05) Final body weight, WG, SGR and FE against dietary BM level had breaking points of 76.2%, 41.7%, 76.5% and 60.0%, respectively, in segmental regression analysis. In conclusion, the results suggest that BM can replace a maximum of 41.7% of FM in the diet of red sea bream without compromising growth performance or feed efficiency for 56 days. 相似文献