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1.
Weena Koeypudsa Amararatne Yakupitiyage & Jirasak Tangtrongpiros 《Aquaculture Research》2005,36(6):570-577
Two experiments were conducted at the Asian Institute of Technology, Pathumthani, Thailand to investigate the fate of chlortetracycline (CTC) residue in chicken manure and its effect on integrated chicken–fish farming system. During the first experiment, broiler chickens were raised and CTC residues in their manure were analysed. Chicken fed diets containing 0, 50, 200 and 800 CTC mg kg?1 had CTC residue levels of 0, 0.9, 3.8 and 6.5 CTC ng g?1. Once the diet containing CTC was withdrawn, CTC in the manure dropped to negligible amounts (0, 0, 0.2 and 0.5 CTC ng g?1) within 1 day. Integrated chicken–fish farming systems were simulated during the second experiment to determine the fate of antibiotic residues in chicken manure in aquaculture environment. Chickens were fed a CTC‐free diet and a feed containing CTC at 200 mg kg?1. Ten 4 m3 square concrete tanks (2 × 2 × 1 m) were used for the experiment. Five tanks were fertilized with CTC‐contaminated manure and the remaining five tanks were fertilized with CTC‐free manure at a rate of 100 kg dry matter ha?1 day?1. Sex‐reversed Nile tilapia (Oreochromis niloticus) was stocked at 12 fish tank?1 on the 14th day after chicken manure application. The immuno‐radio microbial receptor assay (Charm II test) revealed that edible fish muscle, fish intestinal tract and sediment were contaminated by CTC at rates of 7.21, 22.104 and 1.788 ng g?1, respectively, after 45 days. Chlortetracycline was detected on day 20 in the water column and gradually increased from 0.26 to 12.13 ng g?1. Chlortetracycline residues were not detected in fish or the aquatic environment of the CTC‐free treatment. The results demonstrate the potential for antibiotic residue accumulation in fish and aquatic environment when CTC‐contaminated chicken manure is used for pond fertilization. 相似文献
2.
Yeast fermentation integrated with water soaking was applied as a method to reduce the levels of some anti‐nutritional factors in canola meal. The procedure completely eliminated glucosinolates and it reduced phytic acid content by 18%. It also led to increase of 9% of crude protein and 8–32% of some minerals in the meal. A 60‐day feeding trial was conducted to evaluate replacement of dietary soybean meal protein with yeast‐fermented canola meal for Nile tilapia at ratios of 0, 25, 50, 75 and 100% respectively. Three groups of fish with an initial weight of 10 g were fed with each diet twice a day to an apparent satiation. The results showed that there were non‐significant differences (P > 0.05) in growth, survival rate, feed intake and feed conversion ratio for all fish fed with the test diets. However, replacement with 75 and 100% levels significantly reduced (P < 0.05) protein efficiency ratio and nutrient digestibility of protein, lipid, ash, Ca, Mg and P of fish compared with the lower levels. The low retention of protein, lipid, ash, Ca, Mg and P were also observed. These effects seemed to be related to an increased dietary phytic acid. 相似文献
3.
Two semi‐intensive grow‐out trials of Nile tilapia, Oreochromis niloticus (L.), each consisting of seven mixed feeding schedules (rhythmic presentation of high and low protein) and two constant, a high‐protein and the other low‐protein feeding schedules, were carried out simultaneously for 60 days. Mixed feeding schedules were achieved, in Trial 1, by alternating the presentation of a high feed ration (H; 2.3% body weight (BW)) with a low feed ration (L; 1.5% BW) of a single diet A (crude protein content 33%), and in Trial 2, by alternating the presentation of diet A with diet B of a relatively low protein content (crude protein content 22%). In both trials, significant improvements in protein utilization parameters, such as apparent protein conversion efficiency and protein efficiency ratio against continuously high protein feeding were obtained because of the adoption of mixed feeding schedules without any significant decline in the growth parameters such as net fish yield or daily weight gain. In both trials, the mixed feeding schedule ensuring 2 days of high followed by 3 days of low protein presentation, viz. 2H/3L of Trial 1 and 2A/3B of Trial 2 performed the best. Improvement in nutrient utilization in both trials was comparable; however, at existing market prices cost saving because of adoption of mixed feeding schedules was greater in Trial 1. 相似文献
4.
Optimization of Phosphorus Fertilizer in Supplemental Feed‐Fed Based Nile Tilapia (Oreochromis niloticus) Ponds 
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下载免费PDF全文 Moe Thidar Oo A M Shahabuddin Dhirendra P Thakur Aye Aye Mon Amararatne Yakupitiyage Amrit N Bart Ram C Bhujel Jim S Diana 《Aquaculture Research》2015,46(12):2859-2870
An experiment was conducted in earthen ponds at the Asian Institute of Technology, Thailand to determine different phosphorus fertilizer dose effects on Nile tilapia production, water quality variables, nutrient utilization and cost‐benefit under supplemental feeding. Five phosphorus fertilization rates were used as treatments e.g. 100%, 75%, 50%, 25% and 0% of 7 kg P ha week?1. Nitrogen fertilization rate was fixed at 28 kg N ha week?1 for all the treatments. Sex‐reversed Nile tilapia were stocked at 3 fish m?2, and 30% CP floating feed fed at 50% satiation feeding rate. Nutrient budget showed higher phosphorus fertilizer input resulted in higher phosphorus sink in the sediment. Mean weight, mean weight gain, daily weight gain and net yield were not significantly different among treatments (P > 0.05). Total Kjeldahl nitrogen, total phosphorus and soluble reactive phosphorus were significantly different among treatments. Economic analysis showed phosphorus fertilization resulted in positive net returns. Though the gross income was not affected by different fertilization rates, significantly lowest cost was found in the treatment using 25% phosphorus fertilizer. It can be concluded from the research that 25% phosphorus fertilization might be used as an alternative strategy of Nile tilapia pond culture in terms of economic return and nutrient loss in sediment. 相似文献
5.
Growth performance, survival and feed utilization of diploid (2n) and triploid (3n) sex‐reversed male and female Nile tilapia were evaluated at maintenance feeding (1% body weight (BW) day?1), fixed feeding (3% BW day?1) and apparent satiation feeding levels in a freshwater recirculation system comprised of thirty‐six 1‐m3 concrete tanks at the Asian Institute of Technology, Bangkok, Thailand. Triploid Nile tilapia (3n) was produced by subjecting fertilized diploid (2n) tilapia eggs to heat shock. After hatching, fish were sex‐reversed to all‐male and all‐female populations by oral administration of 17 α‐methyltestosterone (60 mg kg?1 feed) and ethynylestradiol (100 mg kg?1 feed) respectively. There was significantly higher growth with increased ration levels in both male and female groups. There were no significant differences in final BW, specific growth rate, survival rate, feed conversion ratio and protein efficiency ratio between diploid and triploid fish. Triploids had lower gonad weights than diploids, and this was particularly evident at the satiation feeding level. Triploid fish had a significantly higher apparent net protein utilization and percentage of gutted weight than diploids at all feeding levels. Higher protein utilization efficiency of triploids might be an advantage for commercial tilapia culture but further research is necessary to make such a conclusion. 相似文献
6.
An experiment was conducted for 8 weeks at the Cantho University, Vietnam, to determine the acceptable level of mangrove leaf litter load and its effect on water quality, growth and survival rate of tiger shrimp (Penaeus monodon). Shrimps were cultured in plastic tanks containing 50 L of brackish water (salinity of 15‰). Leaf litter of Rhizophora apiculata, Avicennia officinalis, Excoecaria agallocha and Acacia auriculiformis were loaded to tanks at rates of 0.0 (control), 0.125, 0.25, 0.5, 1.0 and 2.0 g L− 1 with and without aeration. Tiger shrimp post-larvae (PL; 0.05 ± 0.01 g) obtained from the shrimp hatchery of Cantho University were stocked at a density of 20 PL per tank and fed with pelleted feed containing 38% protein at a rate of 10% body weight (BW) day− 1.
The high leaf-loading rates significantly reduced dissolved oxygen (DO) and survival rates of shrimp in the non-aerated treatments, and all shrimps died after 2 days in the treatments with loading rates above 0.5 g L− 1. Leaf litter loads significantly increased tannin content, chemical oxygen demand (COD), H2S and pH in the aerated treatments. Stepwise regression analysis showed COD, tannin and H2S concentrations had negative effects on shrimp growth in the aerated treatments. Tannin concentration was found to be highest in the treatments with Excoecaria (32 mg L− 1) and Avicennia (24 mg L− 1) leaves. However, there were no significant differences in growth and survival rates of shrimp among the aerobic treatments loaded with different leaf types. The results of this study showed that moderate load of mangrove leaves could play an important role in promoting shrimp growth and survival in aerobic condition. Mangrove leaves at a loading rate of 1 g L− 1 positively influenced both the survival and growth rate of shrimps. 相似文献
7.
An experiment was conducted at the Asian Institute of Technology, Thailand, for 54 days to investigate on the effect of pond water filtration and aggregates (hydroponic substrates) on lettuce (Lactuca sativa L.) production, nutrient uptake and growth. A 2 × 3 factorial experiment consisting of 2 filtration regimes (unfiltered versus partially filtered pond water) and 3 aggregates (styrofoam as control, sand, and gravel). The hydroponic units were placed on a bamboo platform across the pond surface. An earthen pond (226 m2) was stocked with 8000 hybrid catfish with an average initial weight of 6.58 ± 1.72 g. The fish were fed with commercial pelleted feeds containing 30% crude protein. Twenty-one days old lettuce seedlings were transplanted on to hydroponic units after stocking catfish for 4 months in the pond. Pond water was partially filtered by using a settling tank and filtration tank, which contained netting materials to trap solids. Lettuce plots were irrigated twice daily at 0800 and 1600 h using either filtered or unfiltered pond water for 45 min.The highest head weight and yield of lettuce were observed with plants grown on the sand media followed by gravel and the control treatments. Partially filtered pond water treatments had significantly higher lettuce yield (P < 0.05) and filtration increased lettuce yield of the control, gravel and sand treatments by 87, 63 and 52%, respectively, over unfiltered water treatments. Lettuce grown on gravel and the filtered water control treatments had adequate tissue N content. Nutrient rich hybrid catfish (Clarias macrocephalus × Clarias gariepinus) pond water provides an opportunity to use it in the hydroponic vegetable production.Although pond water is mainly constrained by the high suspended solids, and low dissolved oxygen, the study showed that filtration of catfish pond water enhanced the potential to use it for the hydroponic lettuce production. 相似文献
8.
近太湖新银鱼个体虽小 ,生命周期只有 1年 ,但它却在湖北省徐家河水库成为最大的鱼类优势种群 ,形成较大的生产量 ,这是它所具有的独特生物学特性而决定的。经过多年研究 ,特别是通过对1 995年 5月至 1 996年 4月每月采的近太湖新银鱼的样本分析和研究发现 ,与同时生活在该水库的其它硬骨鱼类相比 ,近太湖新银鱼在繁殖方面表现出广泛的繁殖策略。主要表现为 :生殖腺成熟发育时间短 ,完成卵黄沉积的大生长期只需 50d左右 ;繁殖季节早 ,最早的繁殖时间为每年的 2～ 3月 ,繁殖高峰期为 4月中旬 ;繁殖力高 ,单位体重的怀卵量高出该水库其它鱼类 ,平均相对怀卵量为 4 40～ 1 2 2 3粒 /g ;繁殖周期短 ,仔鱼孵出后经过 1 0月即可成熟产卵 相似文献
9.
S. M. Nazmul Alam Bob Pokrant Amararatne Yakupitiyage Michael J. Phillips 《Aquaculture International》2007,15(5):363-370
One hundred and two brackish water shrimp farms in Shyamnagar Upazila of Satkhira District, Bangladesh, were surveyed to study
their costs and returns. Key data were collected, using a questionnaire survey from January to August 2002. Profitability
of operations was affected by fluctuating yields and prices due to diseases, and generated economic risk. The average total
cost of production per hectare was 63,437.57 Bangladeshi taka (tk) (US$1,084.40/ha). The farmers achieved a variable yield
of black tiger shrimp (Penaeus monodon), ranging from 7.48 kg/ha to 455.03 kg/ha, with a mean yield of 146.39 kg/ha, through multi-stock and multi-harvest methods.
The gross and net incomes per hectare were tk49,999.87 (US$854.69) and tk40,307.04 (US$689.01), respectively. Of the total
biomass, 44% came from P. monodon, while the rest (23% and 33%) came from other shrimp and finfish respectively. The return to total cost of P. monodon was a negative profit (tk0.78). 相似文献
10.
Vu Nam Son Nguyen Thanh Phuong Tran Ngoc Hai Amararatne Yakupitiyage 《Aquaculture International》2011,19(3):555-566
Production management of intensive prawn farming strongly differs between dry and wet season in terms of availability and
quality of prawn seeds and water quality. Secondary data implied that prawn seed batches from the market had a total pathogen
infection rate of 53%, predominantly caused by 37% white spot syndrome virus (WSSV), 19% monodon baculovirus (MBV) and 4%
yellow head virus (YHV). Pathogen-free seed batches averaged to 52% during the dry season compared to the wet season (42%).
Survey revealed average stocking density of 17 PL m−2 with a survival rate of 55%, a crop yield of 2,470 kg ha−1 crop−1 and a net income of 6,768 USD ha−1 crop−1. Average production cost amounted to 3.4 USD kg−1, and feed cost accounted for 58% of the production cost. Technical efficiency with respect to prawn yield and survival rate
was higher during the dry season than the wet season. The probability of yield loss was 15.6 times higher in the wet than
in the dry season. A positive net income can be generated for farms operating in the dry season using new ponds and performing
pathogen laboratory tests on prawn seeds before stocking. 相似文献