Gonad development in farmed male and female South African abalone, Haliotis midae, fed artificial and natural diets under a range of husbandry conditions

Background Growth rate is considered one of the most important factors in the farming of Haliotis midae and somatic growth rates decline after abalone reach sexual maturity. Artificial diets are suspected to accelerate maturation, in particular when soya meal is used as a protein source, because of this plant’s high concentration of phytoestrogens. Results We fed two artificial diets and a natural diet, kelp. The first artificial diet had fishmeal as its main source of protein while the other, Abfeed® S34, replaced some of the fish proteins with soya meal. The effect of diet on the gonad development of 27-month-old farmed Haliotis midae, raised at two stocking densities, was analysed. For each gonad sample the development phase was determined based on both histological criteria and the gonad bulk index (GBIn). The hypothesized link between dietary protein source and gonad development could not be established by either morphological criteria or GBIn. Similarly, stocking density did not have a significant effect on GBIn-values. GBIn values were significantly correlated to the results from the histological analyses in males and females. Conclusions The results from this study suggest that artificial diets including those using soya meal are a valid alternative in the feeding of abalone. Moreover, it provides a data base for future research on factors influencing gonad development in this species.

Black Soldier Fly Larvae Can Effectively Degrade Oxytetracycline Bacterial Residue by Means of the Gut Bacterial Community

Antibiotic bacterial residue is a unique hazardous waste, and its safe and effective disposal has always been a concern of pharmaceutical enterprises. This report presents the effective treatment of hazardous waste—antibiotic bacterial residue—by black soldier fly larvae (larvae), oxytetracycline bacterial residue (OBR), and soya meal with mass ratios of 0:1 (soya), 1:20 (OBRlow), and 1:2 (OBRhigh), which were used as substrates for larval bioconversion. Degradation of OBR and oxytetracycline, the bacterial community, the incidence of antibiotic resistance genes (ARGs) and the bacterial function in the gut were examined. When the larvae were harvested, 70.8, 59.3, and 54.5% of the substrates had been consumed for soya, OBRlow and OBRhigh; 65.9 and 63.3% of the oxytetracycline was degraded effectively in OBRlow and OBRhigh, respectively. The larval bacterial communities were affected by OBR, abundant and various ARGs were discovered in the gut, and metabolism was the major predicted function of the gut. These findings show that OBR can be digested and converted by larvae with gut bacteria, and the larvae can be used as a bioremediation tool for the treatment of hazardous waste. Finally, the abundant ARGs in the gut deserve further attention and consideration in environmental health risk assessments.

Evaluation of selected organic residues as supplements on growth and yield of Oyster mushroom, Pleurotus florida

Introduction: The growth and yield of a mushroom are dependent on its ability to utilize the inherent nutrients in the substrate. In order to acquire a good knowledge of the mushroom fruiting substrates, the nutritional contents of the substrate can be improved by the addition of some nitrogenous supplementation to the substrate Methodology: The suitability of some locally available organic materials/wastes as yield boosters for the cultivation of Oyster mushroom Pleurotus florida was evaluated. Corn bran (CB), wheat bran (WB), rice bran (RB), palm kernel cake (PKC), groundnut cake (GNC), soya meal and poultry manure (PM) were separately added to sawdust from Gmelina aborea. Results: Data analysis indicated significant variations among treatments in all the parameters taken. The presence of the various additives in the substrate significantly enhanced the biological efficiency (BE) of the mushroom when compared to the control (p<0.05). P. florida had its highest BE (68.74%) on sawdust added with rice bran (RB) and its least on the control (17.98%). Days to mycelium colonization were shortest on CB (23) and longest on PM (39). Shortest days to primodia initiation were observed on CB (29) and the longest on PM (48). Also, protein content in the fruiting bodies was significantly highest in substrates added with PKC (30.98) and WB (30.94) (p<0.05) and least in control (22.48). Conclusion: It was evident that the inclusion of these additives significantly improved the growth, yield, and nutritional contents of the investigated mushroom. PKC and WB may be used to enhance both the yield and nutritional values of the mushroom.

Soya Bean Meal and Starea Blocks as Protein Supplements for Gestating Beef Cows on Weathered Range

Fifty-two pregnant Hereford and Angus cows, divided according to weight and age into two equal groups, were compared as to their weight changes when grazed on weathered range and fed either soya bean or Starea blocks for 80 days. Weight changes were similar for cows on both protein supplements. As the trials progressed, consumption of Starea supplement declined; that of soya bean meal block remained constant. Cows fed Starea blocks had higher rebreeding rates than did those fed soya meal and their calves (when weaned) weighed more, though differences were not statistically significant.

Sapogenol is a Major Microbial Metabolite in Human Plasma Associated with High Protein Soy-Based Diets: The Relevance for Functional Food Formulations

Legumes are a source of health-promoting macro- and micronutrients, but also contain numerous phytochemicals with useful biological activities, an example of which are saponins. Epidemiological studies suggest that saponins may play a role in protection from cancer and benefit human health by lowering cholesterol. Therefore, they could represent good candidates for specialised functional foods. Following the consumption of a soya-rich high-protein weight-loss diet (SOYA HP WL), the concentrations of Soyasaponin I (SSI) and soyasapogenol B (SSB) were determined in faecal samples from human volunteers (n = 10) and found to be between 1.4 and 17.5 mg per 100 g fresh faecal sample. SSB was the major metabolite identified in volunteers’ plasma (n = 10) after consumption of the soya test meal (SOYA MEAL); the postprandial (3 h after meal) plasma concentration for SSB varied between 48.5 ng/mL to 103.2 ng/mL. The metabolism of SSI by the gut microbiota (in vitro) was also confirmed. This study shows that the main systemic metabolites of soyasaponin are absorbed from the gut and that they are bioavailable in plasma predominantly as conjugates of sapogenol. The metabolism and bioavailability of biologically active molecules represent key information necessary for the efficient development of functional foods.

Impact of Feed Mixture on Kinetic Strength of Pellets for Poultry

The paper presents the impact of feed mixtures for poultry on their kinetic strength determined with Holmen's method. Research material came from a production line and 9 pelleted feed mixtures for poultry with diameter of 3.2 mm were accepted for the research. Feed was prepared, pelleted and cooled with the use of the same devices and their exploitation settings were comparable with regard to the investigated feed pellet. The obtained research results proved that kinetic strength of the investigated feed pellets was statistically significant in relation to the composition of the feed mixture. Relations of kinetic strength of pellets to the composition of the feed mixtures were determined with the multiple regression method. From the determined models the highest utilitarian value may occur in case of a model with four explanatory variables: corn (x1), wheat (x2), soya meal (x4) and fat (x5).