Evaluating the use of alternative proteins in feed on growth and nutrient utilization of Australian catfish, Tandanus tandanus with emphasis on environmental contamination

This study investigated the effects of dietary inclusion of soybean meal (SBM), canola meal (CM), meat and bone meal (MBM), and wheat gluten (WG) on growth performance and waste production of Australian catfish. This investigation also built a general depiction of the use of different ingredients in a single fish species in relation to feeding behaviour.

Untreated WG, SM, CM, and MBM could be used to replace respectively 10%, 15%, 20% and 30% of dietary FM protein without any negative effects on performance of Australian catfish. While dietary SBM improved phosphorus utilisation (PhER) of catfish, dietary CM negatively affected PhER of the fish.
Inclusion of phytase at 3000 FTU/kg enabled SBM to replace 30% dietary FM protein. Replacement of 45% FM protein with SBM was acceptable when methionine, lysine, and phytase were supplemented. Addition of both inorganic phosphorus (P) and limiting AAs significantly improved the growth of catfish fed with SBM as 45% FM replacement though dietary P utilization decreased and P waste from fish elevated.

30% FM protein was replaceable with CM when phytase was supplemented at 1000 – 3000 FTU/kg. Combination of phytase and AAs did not improve the growth of catfish at the replacement rate of 45%. At this level of inclusion, a combination of inorganic phosphorus, methionine and lysine in CM diets significantly improved the growth performance of catfish but had detrimental effects on nutrient utilization of, and P waste from, fish. Total P waste was significantly elevated when more than 30% of dietary FM protein was replaced with CM.

Dietary WG significantly impaired the growth performance of Australian catfish at a very low inclusion level. However, replacing 30% dietary FM protein with WG resulted in significantly lower ortho and total P wastes. 30% dietary FM protein was replaceable with MBM. The daily total P waste of fish was significantly higher when 45% or more FM protein was replaced. The ortho P waste of catfish remained comparable to that of the control fish when 45% of FM protein was replaced. However, 60% FM replacement significantly elevated the ortho P waste of fish.

The effects of organophosphate pesticides on growth of catfish were evaluated by short pulse exposures series of concentrations of chlorpyrifos. The brain AChE of fish was significantly inhibited by chlorpyrifos exposure at the concentration of 0.1µg/L for 22 hours. Brain AChE activity of catfish recovered after transfer to clean water but 30% inhibition of the enzyme was still observed in the fish 2 weeks after transfer to clean water following exposure to 2µg/L of chlorpyrifos for 22 hour. At the exposure concentrations of 0.1 and 0.5µg/L of chlorpyrifos for 22 hours, AChE activity of catfish recovered completely 2 weeks after transfer to clean water. Exposing fish to chlorpyrifos at the concentrations of 2µg/L for 22 hours or 10µg/L for 2 hours significantly impaired the growth performance and feed utilization of catfish. However, the biweekly growth of fish was increased during the 6-week feeding period demonstrating an ability to recover after short term exposure to chlorpyrifos.