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Nutrient digestibility studies in Heteropneustes fossilis (Bloch), Clarias batrachus (Linnaeus) and C. gariepinus (Burchell) 总被引：1，自引：0，他引：1
The apparent digestibility coefficient (ADC %) for protein in catfishes, Clarias batrachus (Linnaeus) (16–18 cm; 45–50 g), C. gariepinus (Burchell) (21–22 cm; 60–65 g) and Heteropneustes fossilis (Bloch) (10–12 cm; 10–15 g) was estimated for nine feedstuffs of plant and animal origin. Fat digestibility was tested for C. batrachus and C. gariepinus, wherein the influence of feeding frequency on protein digestibility was also examined. The digestibility trials were conducted with triplicate groups of 25 fish each in 70‐L polyvinyl indoor flow‐through (1–1.5 L min?1) circular tanks (water volume=55 L). Fish were fed to satiation daily, at 08:00 and 18:00 hours, and faecal matter was collected through slow siphoning. For studying the effect of feeding frequency, fish were fed the experimental diets at 08:00, 11:00, 14:00 and 17:00 hours. The protein digestibility of the feedstuffs varied significantly within each test species. However, the protein digestibility values for most of the ingredients tested were comparable between the three catfish species. The most efficient utilization of protein in these fishes was noted for soybean meal followed by lab‐prepared fishmeal. The lowest protein digestibility was recorded for rice bran. Similarly, the utilization of fat from the feedstuffs was also significantly different within each of the two species, C. batrachus and C. gariepinus. Fat digestibility of feed ingredients was similar between the two species. With respect to the fat, soybean meal, lab‐prepared fishmeal, full‐fat soybean meal and dried fish were more efficiently utilized, while the lowest fat digestibility was obtained for rice bran. A marked decline in protein utilization was observed in the two species where the feeding frequency was increased from two to four times a day. 相似文献
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Mulching of Sclerotium oryzae infested soil (moist or dry) with polyethylene sheets during hot summer days of May and June increased the soil temperature at 5 cm from 36°C (unmulched) to 48°C (wet) and from 44 to 52°C (dry) and at 20cm from 32 to 38°C (wet) and from 35 to 39°C (dry). In artificially-infested soil, the sclerotia were not eradicated but 95–100% loss in viability was observed at 5 cm by a mulch treatment for 1 week and at 20 cm by mulching for 8 weeks. Mulching effects were not influenced by moisture content of soil or by amendments with lucerne or wheat straw. Mulching of naturally-infested soil at a second site did not eradicate S. oryzae but reduced sclerotial viability by 93%. 相似文献
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M. Afzal Khan Ahmad Khalil Jafri Narendra Kumar Chadha & Nazura Usmani 《Aquaculture Nutrition》2003,9(6):391-396
A 56‐day feeding trial was conducted to evaluate growth, feed utilization and body composition of fingerling rohu, Labeo rohita (4.5 ± 0.2 cm; 2.58 ± 0.04 g), fed five isonitrogenous (350 g kg?1 crude protein) and isoenergetic (15.7 kJ g?1 metabolizable energy) diets in which the main protein contributors were: diet I, fish meal (FM); diet II, soybean meal (SBM); diet III, groundnut meal (GNM); diet IV, equal amounts of SBM, GNM and canola meal (CM); diet V, equal amounts of FM, SBM, GNM and CM. Fish were stocked in triplicate groups of 25 fish held in 70 L flow‐through tanks (water volume 55 L) and fed twice daily (0900 and 1700 hrs) to apparent satiation. Fish fed diet I exhibited the highest (P < 0.05) values for live weight gain and specific growth rate (% per day). Feed conversion and protein efficiency ratio were better (P < 0.05) in fish‐fed diets I and II. Fish‐fed diet II exhibited lower (P < 0.05) fat and ash contents in carcass. Based on these findings, a 70‐day trial (Experiment II) was conducted with six diets fed under the same conditions where FM was incrementally replaced with SBM. Fingerling L. rohita (6.7 ± 0.4 cm; 4.07 ± 0.02 g) were used for the study. Crystalline l ‐methionine was added to diets containing more than 250 g kg?1 SBM. This second study showed no significant (P > 0.05) variation in growth, feed utilization and carcass composition for fish fed the different diets. In conclusion, SBM was more effective than GNM or CM, as FM was replaced in feeds for fingerling L. rohita and could completely replace FM when supplemented with methionine and fortified with minerals under the conditions of this study. 相似文献
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An investigation was carried out with 25 populations of Rauwolfia serpentina to assess variability, association of yield components and their direct and indirect effects on yield. Analysis of variance revealed significant differences among 25 populations of R. serpentina for all the traits. Heritability estimates in broad sense were high for most of the traits and moderate for number of primary root branch. As in case of heritability, expected genetic advance was the highest for plant height, number of primary stem branch, reserpine content (%) in root, the most important trait for commercial utilization. Correlation analysis indicated positive and significant phenotypic correlation of reserpine content with root length and total alkaloid content (%) and significant negative association with root diameter. The partitioning of genotypic correlation coefficient into direct and indirect effects revealed total alkaloid content and root yield were the most important direct contributors to reserpine percent in root. It is concluded that accessions with more alkaloid content and root length are likely to yield more reserpine content in root and these characters can be considered to be reliable traits for selection of high reserpine content in root. 相似文献
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Abstract.— The effects of phytic acid on growth, protein efficiency, feed conversion, and carcass composition of mrigal Cirrhinus mrigala fry (2.5–3.5 cm) reared indoors at 18–22 C in 70-L flow-through (1-1.5 L/min) circular tanks were examined. Fish were fed isonitrogenous (40% crude protein) and isocaloric (4.32 kcal/g) purified test diets in the form of moist cake containing different levels (0.5, 1.0, 1.5, 2.0 and 2.5%) of phytic acid (dodecasodiurn salt) at a rate of 4% body weight twice daily (0800 and 1600 h). The highest weight gain (94.87%). specific growth rate (133%). protein efficiency ratio (2.02), and best feed conversion ratio (1.21) were observed in fish fed the control diet containing no phytic acid. Live weight gain and specific growth rate were significantly reduced by dietary phytic acid inclusion above 1%. Dietary inclusion of phytic acid markedly influenced the carcass composition of the fish. Whole body crude protein and fat content declined significantly ( P < 0.05) in fish fed diets containing phytic acid, while percentage of moisture and ash in these fish was significantly ( P ≤ 0.05) higher than fish in control diets. 相似文献
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Effect of fish size and temperature on the utilization of different protein sources in two catfish species 总被引：2，自引：0，他引：2
Two sets of feeding trial were conducted to determine the effect of size and temperature on the utilization of different protein sources in two catfish species. In both the experiments, the fish were fed to apparent satiation daily at 08.00 and 18.00 hours, and faecal matter collected through slow siphoning. The first experiment was designed to study the effect of fish size on apparent digestibility coefficients for plant and animal proteins in the African catfish, Clarias gariepinus (Burchell, 1822). Three size classes (105–109 g; 780–830 g; 1250– 1300 g) of fish were stocked in triplicate sets of 600‐L plastic pools fitted with a flow‐through system (2 L min?1). Within each size class, the apparent digestibility coefficient (ADC) for protein varied significantly with the source and quality of protein used. Soybean meal and fishmeal protein were utilized with greater efficiency, whereas rice bran protein was least digestible. An increase in ADC protein was apparent with increase in fish size for high protein sources such as soybean meal, full‐fat soybean, laboratory‐prepared fishmeal, steam‐cooked brown fishmeal and dried fish. ADC protein for other ingredients decreased with increase in size. In the second experiment, the influence of varying temperature on ADC for protein was determined in the catfish, Heteropneustes fossilis (Bloch) (6–8 g). Triplicate groups of 25 fish were kept at three different ambient temperatures (18, 28 and 38 °C), in 70‐L polyvinyl indoor flow‐through (1–1.5 L min?1) circular tanks (water volume = 55 L). The trend in utilization of protein from different sources remained similar at the three temperatures. For each ingredient, digestibility values obtained at 18 °C were significantly lower than those obtained at 28 °C and 38 °C. Optimal protein utilization in H. fossilis was measured at 28 °C. 相似文献
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During the development of a resistance-monitoring bioassay that uses males as the life-stage tested, the relationship of adult female and male susceptibility of Grapholita molesta to different classes of insecticides was investigated. Preliminary results indicated that more males survived diagnostic doses of azinphos-methyl than females. Additional research revealed that, although the body mass of adult male G molesta was only 69% of that of female moths (5.67 and 8.20 mg, respectively), their LC50 values were 2.6, 4.1 and 10.3 times higher than those of females for azinphosmethyl, malathion and parathion-methyl, respectively. However, female G molesta moths were more tolerant to methomyl than were male moths. There was no indication that this sex-related response occurred in G molesta larvae. The results presented here raise concerns regarding the use of pheromone traps for determining whether insecticide treatments are required and as part of resistance monitoring programs. 相似文献
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