Studies on the improvement of growth performance of Clarias galmaensis through hybridization and genomic DNA from Heterobranchus bidorsalis using sperm mediated gene transfer technique was carried out with the aim of determining the growth performance of Clarias galmaensis treated with genomic DNA and hybridization. Twenty one each of male and female Clarias galmeansis and three each of male and female Heterobranchus bidorsalis were used for the experiment. Female broodstock were induced with ovaprim and kept for latency period, after latency period, one gram (1g) of egg were collected from each fish and fertilized with 1mil of milt collected from the male broodstock. Treatment 1 to 5 involved introduction of genomic DNA of Heterobranchus bidorsalis to the milts at the concentrations of 0, 10, 20, 30 and 40μl before the fertilization while treatment 6 to 8 involved the use of hybridization between Clarias galmaensis and Heterobranchus bidorsalis. After fertilization, the eggs were incubated and raised for 30 days indoors on commercial diets. Thirty (30) fingerlings were selected from each treatment and reared for another four (4) months for growth performance. Data obtained from the research were subjected to analysis of Variance ANOVA. The results shows that the growth performance parameters were better in treatment with ?Female Heterobranchus bidorsalis x ?Male Clarias galmaensis (?Hb x ?Cg) in terms of final mean weight, mean weight gain, mean daily weight gain, percentage weight gain, feed conversion ratio, protein efficiency ratio and percentage survival as 14.26.3g, 1346.7g, 8.86g, 94.38%, 2.07%, 0.50 and 22.43 respectively while final length was higher in breeding combination female and male Clarias galmaensis (Cg x ?Cg) with genomic DNA at 30μl with 1464.7mm. This indicates that Clarias galmeansis can be improved through both hybridization and inclusion of genomic DNA from Heterobranchus bidorsalis.

Viruses are among the most abundant species in the biosphere and may pose a significant risk to the ecology, economy and human health with the discharge of ballast water. The viral pathogens in ballast water have the potential to infect and harm various species of fish and shrimp, leading to economic losses and ecological disruptions. Common to enhance viral management in it. measures such as ballast water exchange and ballast water management system are unsatisfactory for viral disinfection. In this article, we analyzed the abundance and diversity of viral communities in ballast water as well as their potential threat. The results highlight the need to recognize and address the hidden danger of viruses in ballast water. We also assessed the state of ballast water management, emphasizing the importance of implementing effective ballast water management practices to safeguard the health and sustainability of aquaculture systems and offering several suggestions

The MXR (MultiXenobiotic Resistance) phenotype in aquatic organisms is recognized as a biomarker of exposure to contaminants. Previous studies have provided evidence that P-glycoprotein is inducible by organic xenobiotics and overexpressed in mussels from degraded areas. However, seasonal changes in transcript levels at contaminated sites has not been described previously. In this study, tissue-specific gene expression of three ABC transporters was co-analyzed in hemocytes and gills of Mytilus edulis. First, laboratory experiments were conducted under controlled static conditions. An acute short exposure to benzo[a]pyrene showed a modulation of abcb-, abcc- and abcg2-like gene expression with an upregulation in gills and a downregulation in hemocytes. The field study confirmed the trend observed in the laboratory. Abcb- and abcg2-like mRNAs were less abundant in hemocytes originating from the more impacted site by comparison to the reference area. In gills, abcb-like was more expressed in the contaminated mussel group. However, abc gene expression was unstable over sampling seasons. Furthermore, seasonal effects interact with site effects leading even to inversion or to convergence of transcript levels. Only the abcb-like gene displayed more abundant mRNAs levels in gills dissected from animals collected in the more polluted area all over the diachronic study. Taken together, our results confirm the adequacy of abcb-like gene expression in mussel gills as a biomarker of xenobiotic exposure in the field.

This study was carried out to evaluate the effects of sun-dried sicklepod as a replacement for toasted soybean meal in the diets of Clarias gariepinus juveniles. Five iso-nitrogenous diets were formulated at 35% crude protein using Pearson’s square method. Sun-dried sicklepod (SSM) was use to replace toasted soybean meal progressively at 0%, 25%, 50%, 75% and 100% respectively. A total number of one hundred and fifty juveniles of Clarias gariepinus with an average mean weight of 31.19g were procured. The fish were allowed to acclimatize for a day. A complete randomized design (CRD) was adopted. Ten fish were randomly assigned to a 1m2 Hapa net, a total of 15 Hapa nets were used in an outdoor earthen lined pond of 10m × 7m (l × b) and depth of 1.5m, and the five formulated diets were fed to the experimental fish at 5% body weight twice daily and the pond water was monitored. The experiment lasted for 8 weeks. Highest value of mean weight gain was observed in 25% level of inclusion (141.20g) followed by 0% (124.50g), 50% (114.80g) and 75% (108.33g) inclusion level, while the least mean weight gain of 106.00g was recorded in the fish fed 100% inclusion level. The highest of feed conversion ratio was recorded in the control diet with a value of 0.10 while the least (0.07) was recorded in the diet with 25% inclusion level. Highest carcass crude protein of 61.03g/100g was recorded the fish fed 25% inclusion level while the least (58.58g/100g) was obtained in 100% inclusion level. This study revealed that toasted soybean meal can be replaced with sun-dried sicklepod meal up to 25% inclusion level in Clarias gariepinus diets without any negative effects on the growth and nutrient utilization.