Effects of different biological feeds on growth performance, body color, and digestive enzyme activities of Trigonostigma heteromorpha

Trigonostigma heteromorpha is a small freshwater ornamental fish. To determine an appropriate feed formulation for this species, an artificial compound feed was mixed in equal proportions with three types of fresh frozen biological feeds (bloodworms, Artemia, and mysids) and two types of dried insect meals (superworms and black soldier fly). The effects of adding animal-based feeds on the growth, body color, and digestive enzyme activities of the T. heteromorpha were analyzed. The results showed that: (1) When fed Artemia, the weight gain rate (WGR) and weight-specific growth rate (W-SGR) were significantly higher than those in other groups (P<0.05). The specific growth rate of body weight in the superworms group was the lowest, at (1.66±0.30) %·d⁻¹; (2) The feed conversion ratio (FCR) was the lowest in the Artemia group (1.62±0.07), while that in the superworms group (3.39±0.48) was significantly higher than in other groups; (3) Fish fed Artemia showed better overall body color, with superior chromaticity values on the back, tail, abdomen and mid-body region compared with other groups; (4) The activities of lipase (LPS), trypsin (TPS) and pepsin (PES) in the intestine were significantly higher in the Artemia group than in other groups (P<0.05), while the α-amylase (AMS) activity was the highest in the control group; (5) The concentrations of ammonia nitrogen and nitrite in the culture water both showed a trend of increasing first and then decreasing. The peak values were the highest in the superworms group and the lowest in the Artemia group. Therefore, among the five biological feeds tested, Artemia is the most suitable feed for the T. heteromorpha. This study enriches the available data on feeds for T. heteromorpha, helps optimize feed formulations, and promotes the development of broodstock cultivation and seed production techniques for this species.