The uncertainty of feed supply is an understudied welfare issue in the Aquaculture sector. In most scenarios, it is an unforeseen circumstance that could occur due to malfunctioning of fish feeders or delay in maintenance activities before feeding among others. Here, we examined the growth, hematological, and glucose response of Clarias gariepinus exposed to unpredictability feeding stress for 12 weeks. 90 C. gariepinus (10.65±0.11g) were exposed to a predictable feeding time or the control (PFT, T1), early unpredictable feeding time (EUFT, T2), and the late unpredictable feeding time (LUFT, T3) treatments. in triplicates. Growth indices (weight gain (WG), specific growth rate (SGR), and Feed Conversion Ratio (FCR) were observed weekly. Hematological indices from blood samples and glucose response were examined at the end of the study period. Statistical analyses were performed using the generalized linear models in the R statistical package.
The unpredictability in feed supply affected (p≤0.05) the African catfish with similar (p≥0.05) MWG in EUFT and LUFT. FCR was significantly (p≤0.05) different between treatments and the treatment affected (p<0.05) the SGR of the fish. African catfish exposed to PFT had the best condition factor with the least (p≤0.05) mortality rate in T1 (Table 1).
Moreover, WBC, MCH, and MCHC of the fish species were affected (p<0.05) by the treatments (Table 2) and the glucose response increased (p≤0.05) with an increase in the intensity of the unpredictability in feed supply (Fig 1).
In conclusion, our study provides insight into the hematological and growth responses of C. gariepinus when reared at unpredictable feed supply and this could compromise the welfare of C. gariepinus and indirectly affect sustainable fish production.
Keywords: Fish welfare, Hematological response, Fish health, Unpredictable feeding, stress.