Effect of feeding level on growth,body composition,fatty acid profile,and nutrient accumulation in shrimp (<Emphasis Type="Italic">Litopenaeus vannamei</Emphasis>)

A study was conducted in a recirculating aquaculture system (RAS) to assess the growth performance, body composition, fatty acid profile, and nutrient accumulation in different tissues of shrimp using two feeding levels (10 and 16 g/kg^0.8/day). The shrimp PL₂₅ was nursed in the nursing tank for 2 months and stocked in six grow out tanks (ten individuals in each 30 L tank). A commercial feed with 42.7% protein was used over a 16-h period per day. After 4 weeks, the final average weight when fed 16 g/kg^0.8/day was 9.7 g which was not significantly different from a final weight of 8.6 g achieved when feeding 10 g/kg^0.8/day. The protein and energy content increased in high feeding level whereas moisture, crude fat, and ash content decreased with feeding level (P?>?0.05). With the high feeding level, the fatty acid content increased in the eye, muscle, and whole body, with eye containing the highest concentration. The isotopic ratio of δ¹³C was enriched with feeding level in the muscle and whole shrimp whereas the ratio of δ¹³C was depleted in the viscera with feeding level. The fraction of δ¹⁵N was enriched with decreasing feeding level and highest value was found in the muscle than in the whole shrimp and viscera.     

Comparative evaluation of fermented and non-fermented de-oiled rice bran with or without exogenous enzymes supplementation in the diet of <Emphasis Type="Italic">Labeo rohita</Emphasis> (Hamilton, 1822)

A 60-day feeding trial was conducted to study the effect of exogenous enzymes (xylanase and phytase) supplementation in the non-fermented and fermented de-oiled rice bran (DORB)-based diet of Labeo rohita. Four test diets (T1-DORB-based diet, T2-fermented DORB-based diet, T3-phytase and xylanase supplemented DORB-based diet, and T4-phytase and xylanase supplemented fermented DORB-based diet) were formulated and fed to the respective groups. Test diets T3 and T4 were supplemented with 0.01% xylanase (16,000 U kg^?1) and 0.01% phytase (500 U kg^?1) enzymes. One hundred twenty juveniles of L. rohita, with an average weight 5.01?±?0.02 g, were stocked in 12 uniform size plastic rectangular tanks in triplicate with 10 fishes per tank following a completely randomized design (CRD). Exogenous enzyme supplementation to the T3 group significantly improved the growth performance of L. rohita (p?<?0.05). Fermented DORB fed groups registered significantly lower growth irrespective of the supplementation of exogenous enzymes. The carcass composition (except CP %), enzyme activities (except amylase activity), globulin, and A/G ratio did not vary significantly (p?>?0.05). Based on the results of the present study, it is concluded that exogenous enzyme supplementation significantly increases the growth of fish fed with DORB-based diet.     

Effect of dietary synbiotic on growth performance,body composition,digestive enzyme activity and gut microbiota in Cirrhinus mrigala (Ham.) fingerlings

A feeding trial of 60 days was conducted to delineate the effect of dietary synbiotic on maximum growth, body composition, digestive enzyme activity and subsequently gut microbiota in Cirrhinus mrigala fingerlings. One hundred and eighty acclimatized fingerlings of mrigal with initial body weight ranging from 2.87 ± 0.01 g to 3.26 ± 0.05 g were randomly distributed in three replicates of each of four experimental groups including control (without probiotic and prebiotic), T₁ (high probiotic + low prebiotic), T₂ (low probiotic + high prebiotic) and T₃ (high probiotic + high prebiotic), using completely randomized design (CRD). Results showed that growth performance parameters, such as specific growth rate (SGR), per cent weight gain, feed conversion ratio (FCR) and protein efficiency ratio (PER), were reported to be higher in the T₂ group followed by the T₃ group. Maximum gut microbiota activity was found in the T₃ group which was significantly different from other treatment groups. Similarly, body composition and digestive enzyme activity varied significantly (p < .05) among the treatment groups. The study showed the possibility of improved nutrient utilization in terms of growth performance and digestive enzyme activity in the group following dietary synbiotic supplementation.     

Nutritional evaluation of an improved soybean meal as a fishmeal replacer in the diet of Pacific white shrimp,Litopenaeus vannamei

A 12‐week growth trial was conducted to assess an improved soybean meal (ISBM) in the diet of Pacific white shrimp (PWS). Four isonitrogenous and isolipidic experimental diets were formulated: the control diet (ISBM‐0) contained 30% fishmeal (FM) and three test diets (ISBM‐33, ISBM‐66 and ISBM‐100) were formulated by gradually replacing FM on an isonitrogenous basis. Groups of PWS (3.2 g mean initial weight) were fed their respective experimental diets three times per day. Production performance of PWS was unaffected by diet, except the final weight of shrimp‐fed ISBM‐66 diet was significantly lower than those fed ISBM‐0. Whole‐body moisture was significantly higher and protein was significantly lower in PWS‐fed ISBM‐100 versus shrimp‐fed ISBM‐0. PWS‐fed ISBM‐66 had significantly higher oleic acid than shrimp‐fed ISBM‐0 and linolenic acid versus shrimp‐fed ISBM‐0 and ISBM‐100. The lowest linoleic acid and n‐6 polyunsaturated fatty acids levels were found in shrimp‐fed ISBM‐100. Based on second‐degree polynomial regression analysis of final weight and weight gain, the estimated optimum levels of ISBM to replace FM in PWS diets are 89.13% and 95.56% respectively. Overall, results indicate alternative, sustainable, plant‐based protein sources such as ISBM may potentially replace FM in PWS diets.     

Induction of DNA damage in the peripheral blood of zebrafish (Danio rerio) by an agricultural organophosphate pesticide,monocrotophos

The use of organophosphate pesticides (OPs) in agricultural practices in India has gained popularity due to their broad spectrum, low cost and high potency. Monocrotophos (an OP) which is a systemic and contact broad-spectrum cholinesterase inhibitor is being widely used in India. However, its use entails the damage to other non-target organisms such as fish. In the present study, zebrafish (Danio rerio) were exposed to various doses of monocrotophos (0.125, 0.625 and 1.25 μL/L) and genotoxicity studies were carried out employing the comet assay and micronucleus test in the peripheral blood of these fish after 24, 48 and 72 h of exposure. Significant DNA damage in the form of % tail DNA and micronuclei was observed in all the treated fish compared to the control. Both % tail DNA and micronuclei frequency were found to increase significantly as the concentration increased. DNA damage was also observed at all the time intervals for all treatments except in the 0.125 μL/L-treated group. A positive correlation was also observed between the comet assay and micronucleus test. The study thus suggests the use of zebrafish as an experimental model to study the genotoxic effects of agricultural pesticides using the comet assay and micronucleus test.

     

Land-use effects on phosphorus fractions in Indo-Gangetic alluvial soils

Phosphorus (P) in soil exists both in organic and inorganic forms and their relative abundance could determine P supplying capacity of soil. Differential input of exogenous and plant-mediated phosphorus and carbon in soil under different land-uses could influence P availability and fertilizer P management. While the effect of land-use on soil organic carbon (SOC) is fairly well-documented, its effect on soil P fractions is relatively less known. We investigated the effect of different land-uses including rice–wheat, maize–wheat, cotton–wheat cropping systems and poplar-based agroforestry systems on soil P fractions and organic carbon accrual in soils. Total P concentration was the highest under agroforestry (569 mg P kg^?1) and the lowest under maize–wheat (449 mg P kg^?1) cropping systems. On the contrary, soils under rice–wheat had significantly higher available P concentration than the agroforestry systems, probably because of higher fertilizer P application in rice–wheat and prevailing wetland conditions during rice growth. In soils under sole cropping systems viz. rice–wheat, maize–wheat and cotton–wheat, inorganic P was the dominant fraction and accounted for 92.2–94.6% of total P. However, the soils under agroforestry had smaller proportion (73%) of total P existing as inorganic P. Among soil P fractions, water soluble inorganic P (0.13–0.26%) represented the smallest proportion inorganic P in soils under different land-uses. Agroforestry showed significantly (p < 0.05) higher concentrations of SOC than the other land-uses. Soil organic C was significantly correlated with soil P fractions. It was concluded that poplar-based agroforestry systems besides leading to C accrual in soil result in build-up of organic P and the P supplying capacity of soil.     

Predicting upslope expansion of sub-alpine forest in the Makalu Barun National Park,Eastern Nepal,with a hybrid cartographic model

The natural upper boundary of a forest (forest line) in mountain environments is an indicator of climate conditions. An increase in global average temperatures has resulted in an upward advance of the forest line. This advance may result in fragmentation of the alpine ecosystem and a loss of biodiversity. Therefore, it is important to identify potential areas where current forests can advance under scenarios of future climate change. I used expert knowledge and cartographic modeling to create a hybrid cartographic model considering five topographic variables to predict areas where forest line can expand in the future. The prediction accuracy of the model is around 82%. The model is able to predict areas above the current forest line that are suitable or unsuitable for future forest advance. Further inclusion of high-resolution satellite imagery and digital elevation models, as well as field-based information into the model can help to improve the model accuracy.     

Development of a <Emphasis Type="Italic">Cajanus cajanifolius</Emphasis>-based CMS Hybrid Technology in Pigeonpea

Pigeonpea is an important food legume of the semi-arid tropics grown mainly under subsistence agriculture. As a first step to address the five decades-long yield stagnation, a proof-of-concept for a commercially viable CMS-based hybrid technology with high standard heterosis and fertility restoration has been demonstrated. Six generations of backcrossing and selection for male sterility, and agronomic superiority using a Cajanus cajanifolius- (A₄ cytoplasm) based CMS donor (ICPA 2039) and a medium-maturity group recurrent parent ICPL 20176 (ICPB 2043) which resulted in a stable male sterile line (ICPA 2043) with near-perfect male sterility and superior agronomic traits. Following backcrossing and selections, the A-line (ICPA 2043) appeared to be morphologically similar in terms of various qualitative and quantitative traits compared to the B-line (ICPB 2043). However, differences between ICPA 2043 and ICPB 2043 were observed for days to maturity, 100-seed weight, pods plant^-1, and seed weight plant^-1. These differences may not be genetic but physiological. The best heterotic restorer line selected in a cross (ICPH 2671) combination restored a mean of 96.49% male fertility in 36 environments (12 locations, 3 years). Present investigation did not reveal significant G×E interaction for fertility restoration, indicating the possibility of obtaining high and stable grain yields in the pigeonpea growing areas of South and Central India.     

Vacuum press drying studies on two fast-growing Indian wood species

Two fast-growing Indian species, Melia composita Benth. and Eucalyptus tereticornis Sm., which have different sets of physical properties, were dried together in a vacuum press dryer(VPD) under two drying conditions,i.e., above boiling point(ABP) and below boiling point(BBP). The ABP and BBP conditions were maintained by keeping the temperature constant at 75 ℃ and maintaining two pressure levels: 300 mm of Hg(ABP) and 450 mm of Hg(BBP). In order to understand pressure conditions at the core during vacuum drying, a cylindrical brass pipe was inserted in both wood cores and attached with pressure gauges placed outside of the VPD. The results indicate that the Melia wood core attained equilibrium pressure immediately with the pressure of VPD, while Eucalyptus attained it very slowly, reaching equilibrium at later stages of drying when cracks and checks advanced to the core.The drying rate was higher for Melia than Eucalyptus under both drying conditions. The drying rate of Melia(ABP) was higher than Melia(BBP), however, the drying rate for Eucalyptus(ABP) was not significantly different from the BBP drying rate.     

Variability in physical properties of plantation-grown progenies of Melia composita and determination of a kiln-drying schedule

Plantation-grown progenies of Melia composita Willd.were studied for variability in several physical properties: density,radial and tangential shrinkage,longitudinal permeability of heartwood and sapwood.Furthermore,flat-sawn planks from each of the progeny were subjected to a quick-drying test for determination of kilndrying schedule.The mean density of the species was 0.39 g cm~(-3) and the wood may be categorized as light wood.Mean radial shrinkage(%) for the species was 2.8% with progeny-wise variation in radial shrinkage from 1.56 to 4.11%.Mean tangential shrinkage(%) for the species was 5.54% with progeny-wise variation in tangential shrinkage from 3.69 to 7.71%.The resultant tangentialradial shrinkage ratio was 1.98(less than two),which suggests that the wood is relatively stable with respect to drying behavior.Mean sapwood and heartwood longitudinal permeability of the species were 3.38 and 2.02 Darcy,respectively.Higher longitudinal permeability of sapwood and heartwood indicate better drying and preservative properties of the species.Terazawa quick-drying test method suggests that the species is less susceptible to drying defects.During the test,only moderate checks and cracks were observed.A tentative kiln-drying schedule was recommended based on these results.