​​Nursery Rearing of Penaeus vannamei in Biofloc Systems with Different Salinities and Organic Carbon Sources

Background: Nursery rearing of Penaeus vannamei became inevitable in the Indian shrimp farming industry, since intensification of culture practices in grow-out systems caused nitrogenous wastes accumulation, diseases, mortality and premature harvests resulted in high food conversion ratio, lower production and profits. The nursery rearing in traditional water exchange systems often getting failure because of nitrogenous waste accumulation. Hence, the present experiment was planned to rear P. vannamei in bioflocs systems (BFS) with different salinities and carbon sources. Methods: The experiment was conducted in 0.22 m3 tanks with three different salinity groups viz., 35 ppt, 20 ppt and 5 ppt and in each salinity sugar, molasses used as carbon sources to maintain an estimated C/N ratio of 15:1 and controls without carbon sources. Experimental tanks were stocked @6 post larvae/l, with pre-salinity acclimatized P.vannamei seeds having 0.0029±0.0003g size and nursed for a period of 5 weeks. Result: The nitrogenous waste accumulation was reduced significantly (p less than 0.05), also average body weight and survival rate of the seeds showed significant difference (p less than 0.001) between treatments and controls and within treatments (p less than 0.05). Salinity, carbon sources and their interaction influenced the growth characteristics significantly (p less than 0.01). The present experiment manifested promising results of bioflocs nurseries in rearing of P. vannamei seeds at different salinities.

CHARACTERIZATION OF PREDICTED BACTERIAL COLD-ADAPTED LIPASE FROM SEAFOOD COLD STORAGE

Lipases constitute as top three most important group of enzymes along with carbohydrases and proteases, and are widely used in various industries. In particular, lipase that perform high activity at low temperatures, or referred as cold adapted lipase (CLPs) considered as attractive catalyst due to its activity at low temperature. This unique feature is the main advantage of cold adapted lipase utilization because it requires a low energy source that is correlated with lower production costs and energy. In addition, reactions occur in cold temperatures may result in better product quality. The purpose of this research was to perform screening and characterization of bacterial cold adapted lipase from seafood cold storage. Among 53 isolates, Kr_16_30, TI_37_14 and Kr_16_28 showed the highest activity with 4.12 U/mL; 3.87 U/mL and 3.21 U/mL, respectively. Isolates Kr_16_30 seemed to be typical cold adapted lipase with optimum temperature at 20°C and pH 7. Isolates Kr_16_28 performed highest lipolytic activity at 30°C while TI_37_14 suspected to be similar to typical mesophilic lipase with optimum temperature at 40°C. Species identification based on 16s rRDA sequencing revealed that isolates Kr_16 30 and Kr_16 28 are belong to genus Pseudomonas and Bacillus, repectively.

The Physical and Mechanical Properties of Autoclaved Aerated Concrete (AAC) with Recycled AAC as a Partial Replacement for Sand

The application of AAC has increased considerably in Malaysia since the 1990s. The usage of AAC has some advantages, but it also has negative environmental impacts since rejected concrete will become landfill. This study aimed to use AAC waste powder as a material that would partially replace the sand content to produce a new form of Autoclaved Aerated Concrete (AAC). The physical and mechanical properties of the newly developed AAC were investigated. This paper presents improved mechanical and physical properties of the new form of recycled AAC concrete. Besides these improvements, using recycled AAC could lower production costs. Furthermore, the usage of this recycled waste powder is both economically and environmentally advantageous. This study found that when recycled AAC was substituted for sand, AAC with a fine recycled powder content of 30% had a compressive strength that was around 16% higher than conventional AAC and between 29% and 156% higher than any value attained utilizing an industrial waste product. This study also confirmed that the greater strength could be identical to a higher tobermorite phase and that the recycled AAC surface showed a finer crystalline morphology.

Effect of pruning and mechanical fruit thinning on crop load and berry and wine composition of Tempranillo in Texas

Tempranillo is the second most planted variety in Texas. However, over-cropping can be an issue. Crop load can be managed by pruning and mechanical fruit thinning. Mechanizing fruit thinning provides three benefits: yield reduction, berry thinning to decrease cluster compactness and reduce fungal disease and lower production costs than fruit thinning by hand (Tardaguila et al., 2008). In this study, crop load was manipulated by pruning and mechanical fruit thinning and its effect was determined on berry and wine quality.

Assessing the performance of Alphitobius piceus (Oliver, 1792) as novel feeder insect species for small sized postmetamorphic frogs

One of the major difficulties of frog farming is providing adequate food in the first few weeks after the metamorphosis. This is a critical time frame, with rapid growth and high mortality. The established feeder insect species used throughout this delicate stage (cricket and mealworm larvae, adult fruit flies) are suitable from a trophic perspective, but present challenges and difficulties that influence the production costs. The aim of this study is to assess the performance of an alternative feeder species - Alphitobius piceus - with a simpler production technology and a lower production cost. Two species of feeder insect were used: the conventionally used Acheta domestica larvae as control species, and Alphitobius piceus larvae as experimental species. As model anuran we used the European common frog, Rana temporaria. The experimental insect species was easily accepted and produced a strong feeding response in the post-metamophic frogs. There were no significant differences between the control and experimental groups in terms of body condition index and mortality, however survival was better in the experimental group. This similarity indicates a high potential of Alphitobius piceus as feeder species for the newly metamorphosed frogs and also a good economic opportunity for frog farms.

Effect of different fattening period duration on meat productivity of domestic quails

The study was conducted with 224 domestic quails from the specialized meat-type WG line. The duration of fattening period and sex on productive traits, slaughter traits and meat quality of quails was evaluated. The study has shown that the longer duration of the fattening period in quails from the meat-type line WG was associated with lower production efficiency, with more reduction after the 35th day of life. The production efficiency in male quails was lower compared to that in females. The dispersion analysis demonstrated that the determination of 72.2% and 69.6% of dressed carcass weight and deboned meat weight, respectively, depended on fattening period duration (p<0.001). When fattening increased from 28 to 42 days, the amount of feed necessary for one bird increased by 73% and 87%, corresponding to increased costs by 64.5% and 77%. For production of 1 kg dressed quail carcasses, the necessary feed increased by 42.3-45.8% on a weight basis and by 35-37.7% on a cost basis. For production of 1 kg deboned quail meat, corresponding increases are by 42.1-49.5% and 34.8-41.2%, respectively. The period between 28 and 35 days of age was the most appropriate for planning slaughter of WG quails. During that period, the economic efficiency, although already declining, was still within acceptable limits and the increase in quantitative traits in both sexes – still relevant, making the produce more attractive for consumers. With age, the changes in colour characteristics of M. pectoralis superficialis result in darkening of meat (p<0.001). Thus, it assumes nuances specific rather for game meat. This effect is desirable, as it improves the commercial presentation of domestic quail meat in line with consumers’ attitudes.

A comprehensive comparison between camelid nanobodies and single chain variable fragments

By the emergence of recombinant DNA technology, many antibody fragments have been developed devoid of undesired properties of natural immunoglobulins. Among them, camelid heavy-chain variable domains (VHHs) and single-chain variable fragments (scFvs) are the most favored ones. While scFv is used widely in various applications, camelid antibodies (VHHs) can serve as an alternative because of their superior chemical and physical properties such as higher solubility, stability, smaller size, and lower production cost. Here, these two counterparts are compared in structure and properties to identify which one is more suitable for each of their various therapeutic, diagnosis, and research applications.

Nutrients and Energy Digestibility of Microalgal Biomass for Fish Feed Applications

Aquafeed accounts for at least 75–90% of aquaculture’s operating costs. Traditional aquafeed ingredients such as fishmeal, fish oil, and soybean meal are unsustainable; further, their increasing cost necessities developing alternative feed ingredients. Microalgae-based aquafeed is not only environmentally friendly, but it can also be cost-effective with proper optimization. In addition, the nutrition profile of microalgae is similar to that of many fishes. The digestibility of a feed is one of the most important factors to consider in feed formulation. A highly digestible feed can lower production costs, reduce feed waste, and reduce the risk of eutrophication. This review discusses the digestibility of various nutrients such as protein, lipid, carbohydrate, amino acids, and fatty acids (including omega-3 fatty acids), dry matter, and energy of various microalgae in fish. Other commonly used aquafeed ingredients were also compared to microalgae in terms of nutrient and energy digestibility in fish. The intrinsic characteristics of microalgae, biomass pretreatment, and feed preparation methods are all discussed as factors that contribute to the nutrient and energy digestibility of microalgae in fish. Furthermore, methods for increasing the digestibility of microalgal biomass in fish are suggested. Finally, the review concludes with the challenges and prospects of using microalgae as a fish feed in terms of digestibility.

Hydro-Thermal Modeling for Geothermal Energy Extraction from Soultz-sous-Forêts, France

The deep geothermal energy project at Soultz-sous-Forêts is located in the Upper Rhine Graben, France. As part of the Multidisciplinary and multi-contact demonstration of EGS exploration and Exploitation Techniques and potentials (MEET) project, this study aimed to evaluate the possibility of extracting higher amounts of energy from the existing industrial infrastructure. To achieve this objective, the effect of reinjecting fluid at lower temperature than the current fluid injection temperature of 70 °C was modeled and the drop in the production wellhead temperature for 100 years of operation was quantified. Two injection-production rate scenarios were considered and compared for their effect on overall production wellhead temperature. For each scenario, reinjection temperatures of 40, 50, and 60 °C were chosen and compared with the 70 °C injection case. For the lower production rate scenario, the results show that the production wellhead temperature is approximately 1–1.5 °C higher than for the higher production rate scenario after 100 years of operation. In conclusion, no significant thermal breakthrough was observed with the applied flow rates and lowered injection temperatures even after 100 years of operation.

Effect of supplementing feed grade L-methionine in plant sourced diet on the performance of broiler chicken

The study was conducted to investigate the productivity and profitability of broiler on L-methionine supplemented diet. A total of 160 day-old broiler chicks (Cobb 500) was randomly distributed to four dietary supplements, D0 (Control), D1 (0.30 % L-Met), D2 (0.35 % L- Met) and D3 (0.40 % L- Met). Each treatment was replicated five times with 8 birds per cage. The chicks were reared in the battery cages while they were fed with broiler starter diet (crumble) until Day14 of age. The birds with fed with L-Met supplemented diets starting from Day15 until Day35 of age All the diets were iso-caloric and iso-nitrogenous.. Results revealed that the L-Met supplementations were in favor of higher live weight (LW) and better (p<0.05) feed conversion ratio without affecting the feed intake (FI). The D3 diet resulted higher (p<0.01) LW in the birds than all others on Day35 of age. The livability (%) was unaffected (p>0.05) by the dietary supplements. No significant (p>0.05) difference was observed in the relative weights of visceral organs (small intestine, proventriculus, gizzard, liver and heart) except for the spleen. Relatively increased (p<0.05) spleen weight (%) was observed in the D3 diet. The breast weight (%) was increased marginally (p<0.07) in the D3 group, while the other carcass parts; breast weight, thigh weight, wing weight, shank weight, drumstick weight, neck weight, and abdominal fat content were found to be similar (p>0.05) in the dietary groups. Higher profit (p<0.01) and lower production cost (p<0.05) were observed in the D3 group than that of the others. It can be inferred that 0.40% L-Met supplementation in the broiler diet is better for growth performance and profitability. Bang. J. Livs. Res. Vol. 27 (1&2), 2020: P. 1-14