Agroforestry Systems - Complex agroforestry systems are suggested as a possible solution to reduce the effects of deforestation in the tropics while enhancing the livelihoods of local human... 相似文献
Though Biofloc Technology is a new concept in Bangladesh, it provides advantages for improving aquaculture production in many countries, leading to achieve sustainable development goals. The objectives of this study were to determine the effects of stocking densities on the growth performance of stinging catfish (Heteropneustes fossilis) under Biofloc Technology and assess the economic prospects and business feasibilities. Fingerlings were stocked in unique 5000-L tanks with three stocking densities, i.e., 3500 fish/tank (Treatment-I), 4000 fish/tank (Treatment-II), 4500 fish/tank (Treatment-III). The treatments showed significant differences (P?<?0.05) considering the species-specific growth rate, feed conversion ratio, and protein efficiency ratio. Treatment-I had significantly ((P?<?0.05) higher final biomass (29.51 ± 0.04 kg/m3) than the other treatments. The present findings revealed that using a lower stocking density, the Biofloc Technology reduced ammonia (NH3), nitrite (NO2), nitrate (NO3), TDS, and floc volume but significantly increased the dissolved oxygen. As a result, Treatment-I had generated significantly higher net income (BANGLADESHI TAKA—BDT 86,278.90) over the other treatments. Moreover, the NPV, net BCR, and RoR with 4% and 9% opportunity cost were also significantly higher in Treatment-I than other treatments. The internal rate of return (IRR) and SWOT analysis index indicates that investing in Biofloc Technology is far superior, and a stocking density of 3500 fish/tank (Treatment-I) resulted in a faster investment return.
In order to use rice straw as forage in livestock feeding, the effects of steam-treated rice straw (at 15.5 kgf/cm2 for 120 s) feeding on growth performance, plasma volatile fatty acid profile, and nutrient digestibility of goats were determined. Twenty male goats (18.69?±?0.34 kg) were used in an 84-day trial. The goats were divided into four groups of five goats each to receive steam-treated (STRS) or untreated (UTRS) rice straw diet under closed house (CH) and open house (OH) systems. The results revealed that the goats fed with STRS had significantly higher dry matter (DM), organic matter (OM), crude protein (CP), neutral detergent fiber (NDF), and acid detergent fiber (ADF) digestibility; similarly, the average daily weight gain and feed conversion ratio were higher for STRS groups under both CH and OH systems than those for UTRS. The plasma protein and insulin in STRS and cholesterol in UTRS groups was higher (P?0.05) at 60 days but found not different (P?>?0.05) at 30 days. The plasma amylase, lipase, T3, T4 and glucagon at 30 and 60 days were not different (P?>?0.05) among the groups. The plasma acetate, propionate, butyrate, and total volatile fatty acid were higher (P?0.05) in STRS groups at 30 and 60 days. The housing conditions had no effects (P?>?0.05) on these parameters. It could be concluded that steam treatment of rice straw at 15.5 kgf/cm2 for 120 s increased apparent nutrient digestibility, hence increased the growth and feed efficiency of growing goats. 相似文献
In recent years, some outbreaks of skin lesions suspected to be avian pox were observed in the backyard poultry in different parts of western areas in Iran. Consequently, 328 backyard poultries with suspected signs of avian pox virus infection were sampled. All birds showed nodular lesions on unfeathered head skin and/or fibronecrotic lesions on mucus membrane of the oral cavity and upper respiratory tract. For histopathological analysis, the sections of tissue samples from cutaneous lesions of examined birds were stained with H&E method. For PCR, after DNA extraction a 578-bp fragment of avian pox virus from 4b core protein gene was amplified. Results showed 217 and 265 out of 328 (66.1 and 80.7 %, respectively) samples were positive for avian pox virus on histopathological and PCR examination, respectively. In this study, the samples that had intracytoplasmic inclusion bodies on pathologic examination were PCR positive. This study revealed that PCR is a valuable tool for identification of an avian pox virus and that the frequency of pox infection in backyard poultry in western areas of Iran is high. 相似文献
The present research investigated the effect of stocking density on pond (75 m2, depth 1.2 m) production of Nile tilapia (Oreochromis niloticus) and freshwater prawn (Macrobrachium rosenbergii) stocked at a fixed 3:1 tilapia:prawn ratio. Three stocking densities were tried in triplicate: 20 000 ha−1 (treatment TP‐20), 30 000 ha−1 (TP‐30) and 40 000 ha−1 (TP‐40). The ponds were provided with bamboo as substrate for periphyton development. Bamboo poles (mean diameter 5.5 cm and 5.0 poles m−2) were posted vertically into pond bottoms, resulting in 60% additional substrate area in each pond. On average, 43 genera of algae and 17 genera of zooplankton were identified from pond water, whereas 42 genera of algae and six genera of microfauna were attached to bamboo substrates. No differences were observed between treatments in the ash‐free dry matter (AFDM), chlorophyll a and phaeophytin a content of periphyton (P>0.05). Survival of tilapia and prawn and individual weight gain of tilapia were lower (P<0.05) in treatment TP‐40. The net yields were higher (P<0.05) in treatments TP‐30 (2209 and 163 kg ha−1 105 day−1 of tilapia and prawn respectively) and TP‐40 (2162 and 141 kg ha−1 of tilapia and prawn respectively) than in treatment TP‐20 (1505 and 136 kg ha−1 of tilapia and prawn respectively). The net tilapia yields were quadratic correlated (R2=0.92) with fish stocking density. The cost–benefit analysis shows that the net profit margin was highest in treatment TP‐30 (69%), followed by TP‐20 (50%) and TP‐40 (44%). 相似文献
This study shows that alternatives for fishmeal in a fish diet affect not only fish growth but also faeces stability and nitrogen (N) and phosphorus (P) waste production. Wheat gluten diet (WGD), soybean meal extract diet (SBE), soybean meal diet (SBM), duckweed diet (DWD) and single‐cell protein diet (SCP) were evaluated as a fishmeal replacement on a 15% weight weight?1 basis in tilapia diets. Fishmeal replacement affected dry matter (dm), protein, ash and P digestibility significantly. Faeces recovery (6.8–11.2%) was not significantly affected, although the amount of non‐recovered faeces and total faeces showed significant differences. Duckweed diet and SCP resulted in the largest amounts of non‐recovered and total faeces (199–210, 224–225 g dm kg?1 feed dm). Compared with fishmeal diet (FMD), the WGD and SBE resulted in similar growth, but higher non‐faecal N losses (471–495 vs. 416 g N kg?1 N). Soybean meal diet, DWD and SCP resulted in lower growth but less non‐faecal loss (409–450 g N kg?1 N). The DWD and FMD had the highest N retention (480 g N kg?1 N) compared with the other diets (431–451 g N kg?1 N). Carbon retention, faecal and non‐faecal losses and P retention were similar for all diets (302–358, 142–176 and 489–523g C kg?1 C, 606–704 g P kg?1 P). Phosphorus faecal loss was lower for all diets (329–381 g P kg?1 P) than for the FMD (401 g P kg?1 P). 相似文献
The bleached jute fabric (BJF) reinforced polypropylene (PP) composites with various contents of acrylic acid (AA)-treated BJF and un-AA-treated BJF were fabricated by compression moulding method at 190 °C. The AA-grafted BJF reinforced PP composites were then irradiated by γ-ray at various doses. The mechanical properties of neat PP (N-P), ungrafted-BJF and PP composites (UG-BJFPC), AA-grafted-BJF and PP composites (AA-BJFPC) and γ-ray cum AA-grafted-BJF and PP composites (γAA-BJFPC) show maximum tensile strength (TS) of 30, 46, 47 and 51 MPa, maximum flexural strength (FS) of 34, 49, 50 and 54 MPa and maximum Young’s modulus (E) of 280, 428, 436, and 680 MPa, respectively. The increase of TS, FS and E from UG-BJFPC are 2 %, 2 %, and 2 % for AA-BJFPC and 11 %, 10 % and 59 % for γAA-BJFPC. The TS, FS and E are found to increase with radiation dose up to 500Krad and then decrease. The water absorption (WA) for UG-BJFPC, AA-BJFPC and γAA-BJFPC is respectively about 14, 10 and 9 %, indicating a gradual development of hydrophobic character of the composites first by AA-treatment and then by γ-ray-treatment. AA treatment on jute fabric and gamma irradiation on composite result in significant change of morphology of the jute fabric composites surface and better mechanical bonding between fabric and polymer matrix, as a result improved mechanical properties are found. 相似文献
The aim of this work was to evaluate the effective parameters for prediction of the electrospun gelatin nanofibers diameter using artificial neural network (ANN) technique. The various sets of electrospinning process including temperature, applied voltage and polymer and solvent concentrations were designed to produce pure gelatin nanofibers. The obtained results by analyzing Scanning Electron Microscopy (SEM) images indicated that the produced nanofibers diameter was in the range of 85 to 750 nm. Due to the volume of the data, k fold cross-validation method was used for data setting. Data were divided into the five categories and trained and tested using ANN technique. The results indicated that the network including 4 input variables, 3 hidden layers with 10, 18 and 9 nodes in each layers, respectively, and one output layer had the best performance in the testing sets. The mean squared error (MSE) and linear regression (R) between observed and predicted nanofibers diameter were 0.1531 and 0.9424, respectively. The obtained results demonstrated that the selected neural network model had acceptable performance for evaluating involved parameters and prediction of nanofibers diameter. 相似文献