Tetraselmis chuii biomass as a potential feed additive to improve survival and oxidative stress status of Pacific white-leg shrimp Litopenaeus vannamei postlarvae

International Aquatic Research - Shrimp is an important traded fishery commodity. When subjected to stress, shrimp usually suffers from oxidative stress, which leads to cell injury, senescence, and...     

Increased androgen receptor expression in muscle tissue contributing to growth increase in androgen-treated Nile tilapia

The aim of this study was to investigate the molecular mechanism behind androgen-induced sex reversal and growth increase in Nile tilapia. Three-day-old mixed-sex tilapia juveniles were treated with differential dose (0, 5, 10, 20, 30 mg/kg diet) and duration (0, 15, 30, 45, 60 days) regimes of 17α-methyltestosterone. Treatment regimes 10, 20, 30 mg/kg-30, 45, 60 days showed ~95% males, while 0 mg/kg-0 days (control) showed ~50% males (P < 0.01). Next, tilapia was cultured for 6 months in cistern and pond culture systems with 17α-methyltestosterone-treated diet (10 mg/kg) for three different durations: 0 days (control), 30 days (30-day-treated), and 180 days (throughout-treated). Fish in pond culture showed significantly higher (P < 0.05) final weight compared with tilapia in cistern culture (235.76, 156.82 g, respectively). Both 30-day-treated and throughout-treated fish showed significantly higher (P < 0.05) final weight, length, daily weight gain, specific growth rate, and muscle protein content compared with control fish. The androgen receptor β mRNA and protein expression levels in both 30-day-treated and throughout-treated fish were significantly higher (~twofolds, P < 0.05) compared with hormone-untreated control males. However, there was not much difference for all these parameters among the two hormone-treated groups. This higher growth probably results from an androgen-induced increased ‘androgen-androgen receptor’ mediated anabolic pathway. Serum testosterone concentration of 30-day-treated fish after 6 months was similar to that of control males (0.9 ng/ml). Moreover, culture of 17α-methyltestosterone-treated monosex tilapia was found beneficial than hormone-untreated mixed-sex tilapia culture for maintenance of natural fish diversity in indigenous water bodies.     

The annual reproductive cycle and sex inversion of the Picnic seabream,Acanthopagrus berda (Forsskål 1775) from Indian waters: Histological and morphometric description

The annual reproductive cycle of picnic seabream, Acanthopagrus berda (Forsskål, 1775), one of the potential aquaculture candidate from estuarine waters of Calicut, Kerala (India) was studied. Based on the morphological and histological studies, the ovotestes of A. berda were classified as active male, active female, inactive male, inactive female, transitional and undifferentiated. Histological observation of transitional gonads showed signs of degeneration in the testicular lobe, proliferation of connective tissue and empty sperm ducts indicating protandrous hermaphroditism in A. berda. Ovary was classified into seven maturity stages (virgin, developing virgin, developing, maturing, mature, running, spent) and testis into five maturity stages (resting, maturing, mature, running, spent). Gonadal development in A. berda indicated resting phase (February–July), pre‐spawning phase (March–August) and spawning phase (August–December). Inactive (24.6%) and active males (21.6%) were observed as dominant in smaller length classes (140–250 mm TL), whereas inactive (18%) and active females (51%) were observed as dominant in larger length classes (251–450 mm TL). Few primary females (28.1%) were observed in smaller (below 250 mm TL) and few primary males (28.5%) were observed in larger length classes (above 250 mm TL). From the present study, it can be concluded that in A. berda, most of the individuals function first as males and then change sex to female, but few continue to function as either male or female throughout their lifespan indicating digynous protandrous hermaphroditism.     

Pharmacokinetics and distribution of sulphadimidine in plasma,milk and uterine fluid of female buffaloes

The pharmacokinetics of sulphadimidine after a single dose (200 mg/kg i.v.) was studied in five healthy lactating buffaloes. The study revealed that the drug attained its peak concentration of 314.0±13.0, 242.4±3.0 and 100.2±2.5 g/ml at 15 min, 30 min and 12 h in plasma, milk and uterine fluid, respectively. The pharmacokinetic parameters calculated by a 2-compartment open model gave values for t₁, t₁ and vd_area of 2.10±0.36 h, 12.36±0.57 h and 1.23±0.07 L/Kg, respectively. A high vd_area as well as a value of 0.74±0.08 for K₁₂:K₂₁- (tissue Plasma) indicates better penetration of the drug into the different body fluids and tissues, which is further supported by a high concentration obtained in milk and uterine fluid. The therapeutic concentration (50 g/ml) was maintained for around 24 h in plasma and milk and 12 h in uterine fluid. The results suggest that, apart from its use in systemic infections, the drug can be effectively used by the i.v. route in uterine and mammary gland infections. The dosages for maintaining concentration of 50 g/ml, 100 g/ml and 150 g/ml at convenient dosage intervals of 12 and 24 h were also determined.     

Enzymatic Peeling of Potato: A Novel Processing Technology

Development of an innovative biotechnological method for potato peeling, closer to the ‘ideal’ peeling conditions of the product, was the main objective of the present research. Studies on enzymatic hydrolysis of potato peel were conducted. The efficacy of enzymatic peel hydrolysis was expressed in terms of reducing sugar content of the enzyme solution in which potato peel was incubated. Enzyme screening revealed that an enzyme solution containing a cellulase-xylanase mixture and amylase in a ratio of 1:1 showed good peel hydrolyzing efficiency of peeled peels. To further maximise the peel hydrolysis, condition parameters were optimised using response surface methodology (RSM). At the optimised conditions of 60 °C, pH 6 and 4 h, the reducing sugar yield in the solution was maximum. Characterization of the potato peel using microscopic techniques (scanning electron microscopy (SEM), atomic force microscopy (AFM)) further illustrated degradation of cell wall and reduction in the surface roughness of the peel after enzymatic treatment, which could enhance peel loosening from the intact potato. To further ascertain the efficiency of the process, studies were conducted with the selected enzyme on intact potato tubers under optimised conditions. Easy removal of peel was observed in enzyme-treated potato tubers, which showed 0.52% peel loss by abrasive peeling. The present process employing enzymes could be applied for peeling of intact potato as an alternative to conventional peeling process.     

Herbicide ready-mixes effects on weed control efficacy,non-target and residual toxicities,productivity and profitability in sugarcane–green gram cropping system

Weeds pose a major challenge at the initial stages of sugarcane and when uncontrolled cause high yield losses. This study was undertaken to define a better and cost-effective weed management strategy. We compared ametryn + trifloxysulfuron-sodium (hereafter referred to as trifloxysulfuron) ready-mixes with single applications of trifloxysulfuron, atrazine and 2,4-D for efficacy, non-target and residual toxicities, yield and profitability in a sugarcane–green gram rotation. Results showed that a density of 100 weeds m^?2 could reduce sugarcane yield by 18.4 t ha^?1. The ready-mix ametryn + trifloxysulfuron (1097.3 + 27.8) g a.i. ha^?1 applied 15 days after planting (DAP) caused reductions in weed density by 88.2%, 90.9%, and 90.3%, and weed biomass by 68.0%, 53.8%, and 56.2% compared to unweeded control at 30, 60, and 90 DAP, respectively. Consequently, the sugarcane yield, system productivity, and net returns were increased by 92.1%, 43.5%, and 1515%, respectively due to this ready-mix. It increased system productivity by 23%, 17.2%, and 22.7% compared to trifloxysulfuron, atrazine, and 2,4-D treatments, respectively. This ready-mix may be recommended in sugarcane. This would reduce weed seed bank and herbicide application cost by 50%, and prevent/delay weed shift and resistance.     

Use of microalgal‐enriched Diaphanosoma celebensis Stingelin, 1900 for rearing Litopenaeus vannamei (Boone, 1931) postlarvae

The present work investigates the effects of Chaetoceros calcitrans, Nannochloropsis oculata, Tetraselmis tetrahele and Isochrysis galbana diets on the lifespan, growth, neonate production and the nutritional profile of Diaphanosoma celebensis. In addition, the effects of enriched D. celebensis on the survival and growth of Litopenaeus vannamei postlarvae (PLs) was compared with Artemia. Results showed that significantly higher (P < 0.05) neonate production of D. celebensis was attained when fed with C. calcitrans compared to the other microalgae. In addition, D. celebensis fed on C. calcitrans had significantly higher levels (P < 0.05) of protein, lipid and carbohydrate compared to the other three microalgae. On the other hand, D. celebensis had a significantly (P < 0.05) longer lifespan when fed on N. oculata and T. tetrahele compared to those fed with C. calcitrans and I. galbana. Shrimp PLs fed D. celebensis enriched with C. calcitrans had higher survival and specific growth rate but it was not significantly different (P > 0.05) from PL fed only Artemia, indicating that D. celebensis has potential to be used as live feed for the hatchery rearing of L. vannamei PLs, in place of Artemia. This study illustrated that the quality of the D. celebensis production and proximate composition was highly correlated with the food type, and it can be used as a valuable live feed for shrimp larviculture.     

Comparison of organic and conventional farming for onion yield,biochemical quality,soil organic carbon,and microbial population

In an ongoing field experiment, organic and conventional farming (control) were compared for onion bulb yield, biochemical quality, soil organic carbon (SOC), and microbial activity after the sixth cropping cycle. The treatments used for organic production were farmyard manure (FYM, 20,000 kg ha^?1), poultry manure (PM, 10,000 kg ha^?1), vermicompost (VC, 10,000 kg ha^?1), neem cake (NC, 5000 kg ha^?1), and a combination of FYM (5000 kg ha^?1), PM (2500 kg ha^?1), VC (2500 kg ha^?1), and NC (1250 kg ha^?1); all treatments were compared with the control. Organic treatments produced 24.6–43.6% lower yield consistently for 6 years than the control treatment. No significant difference was observed between PM, FYM, and VC treatments for the bulb yield. Bulb analysis during the sixth year indicated that plants that received FYM, PM, or VC had higher levels of total phenol, total flavonoid, ascorbic acid, and quercetin-3-glucoside than the control plants. All the five organically treated sets had significantly higher values of SOC, microbial population, fungal-to-bacterial ratio, and dehydrogenase activity than the control and the initial values in each treated set. The results indicate that FYM, PM, or VC application enhances biochemical quality and organic farming is more sustainable than conventional farming.     

Analysis of genetic architecture for some physiological characters in sesame (<Emphasis Type="Italic">Sesamum indicum</Emphasis> L.)

Combining ability for some important physiological parameters in sesame were examined to understand the nature of gene action and to identify parents for breeding programme. Seven diverse genotypes of sesame, their 21 F₁s and 21 F₂s were grown in summer, 2003, in a randomized complete block design with three replications. Data were collected on leaf area index (LAI) at 30, 45, 60 and 75 days after sowing (DAS), crop growth rate (CGR) estimated between 30–45 DAS, 45–60 DAS and 60–75 DAS, days to peak flowering (DPF), duration of flowering (DF), duration from peak flowering to maturity (DFM), oil content in percentage (OC) and oil yield (OY) plant⁻¹. Analysis of combining ability was done on the above physiological characters following Method-2, Model-I of Griffing (Aust J Biol Sci 9:463–493 1956). Variances due to general combining ability (GCA) and specific combining ability (SCA) for all the physiological traits were highly significant in both F₁ and F₂ generations indicating importance of both additive and non-additive gene actions for the inheritance of all the physiological characters in both F₁ and F₂ generations. Preponderance of non-additive gene action was recorded for CGRs, LAI 3, LAI 4, DPF, DF and OY in both the F₁ and the F₂ generations. For OC additive gene action was predominant in F₁ while non-additive gene action in F₂. The genotype OS-Sel-2 appeared as best overall general combiner in both the F₁ and the F₂ generations. For DPF, DF and DFM, the variety B 67 was best general combiner, followed by CST 2002, which could be utilized for developing early flowering and early maturing lines with determinate growth habit. Association between GCA-effects and mean performance of the parents suggested that the performance per se could be a good indicator of its ability to transmit the desirable attributes to its progenies. Crosses CST 2002 × TKG 22, CST 2002 × MT 34, MT 34 × AAUDT 9304-14-4, AAUDT 9304-14-4 × B 67, TKG 22 × Rama and TKG 22 × B 67 which showed high SCA-effect for OY, also exhibited positive and significant SCA-effects for other physiological component characters in F₁ generation. The overall results indicated that crosses CST 2002 × TKG 22 and MT 34 × AAUDT 9304-14-4 could be utilized for development of high oil yielding hybrids. The crosses OS-Sel-2 × AAUDT 9304-14-4, AAUDT 9304-14-4 × B 67 and MT 34 × OS-Sel-2 could be promising for isolation of superior recombinants for high oil yield coupled with early maturity and other growth characters in advanced generations of segregation. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.