Dietary supplementation of wheatgrass powder to assess somatic response of juvenile grass carp (Ctenopharyngodon idella)

Abstract

Consequence of dietary fish meal substitution with wheatgrass was evaluated by observing growth response, associated feed cost and survival of grass carp (Ctenopharyngodonidella) fingerlings for sixty days. Sprouted wheatgrass (Triticumaestivum) was prepared for its inexpensively rich nutrients. Four isonitrogenous test diets were formulated and applied as treatments (T) in triplicates (R). In the control (T₁), basal inclusion rate of fish meal was 30%, of which 10% was replaced with wheatgrass powder in T₂ and in T₃ replacement was 20%. In contrast, 30% of basal fishmeal was replaced in T₄. Grass carp fingerlings (6.38±0.21 cm and 2.83±0.36 g) were stocked in twelve aquaria (60×40×45 cm³) each containing 75 L water, at 10 fish per aquarium, fed test diets at 5% of body weight twice daily. Prominent effect of wheatgrass supplementation was found on food conversion ratio (FCR) and survival rates. The significantly lowest FCR was observed in T₃ (2.13±0.42) followed by T₂ (2.89±0.99), T₁ (3.01±1.53) and T₄ (3.05±0.94). Besides, fish survival rate was significantly improved in T₂ (90%), T₃ (93.33%) and T₄ (93.33%) compared to the lowest survival in T₁ (83.33%). In conformity, fish tolerance (LT50) to low pH stressor was also increased with wheatgrass supplementation. The other growth parameters among the treatments were statistically similar with highest specific growth rate and fish production in T₃ (1.13±0.12 %/day and 2.28±0.13 tons/ha). Dietary wheatgrass did not affect the fish carcass composition rather gave better result to some extents. The significantly highest carcass protein and lowest moisture was retained in T₃ (14.13±0.05% and 74.91±0.25% respectively), whereas comparatively higher lipid and mineral (ash) content was found in T₁ (7.69±0.02% and 2.35±0.27% respectively). Importantly, feed formulation cost was reduced by 2.61, 4.89, and 7.71% in T₂, T₃, and T₄ respectively compared to T₁. Therefore, wheatgrass could be promising in juvenile grass carp diet.

Asian J. Med. Biol. Res. September 2020, 6(3): 482-490