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<p>Aquaculture plays a vital role in meeting the growing global demand for high-quality protein, particularly in the context of a rapidly increasing human population. <i>Channa striata</i> is an important aquaculture species due to its high nutritional value, rapid growth and adaptability to diverse environmental conditions. However, the demand for <i>C. striata</i> cannot be met due to the limited availability of its seed, as low larval survival remains a significant challenge in hatchery production. Therefore, the present study aimed at studying the influence of dietary taurine supplementation on the growth and survival of <i>C. striata</i> larvae by understanding the ontogeny of digestive enzyme activity. Hence, the study was conducted as two experiments. In the first experiment, the ontogeny of digestive enzyme activity in <i>C. striata</i> larvae was examined to assess the optimal weaning stage. To facilitate this, larvae were sampled at 3, 6, 9, 12, 15, 18, 21, 25 and 30 days post-hatch (dph). The activities of digestive enzymes such as trypsin, chymotrypsin, leucine aminopeptidase and lipase peaked at 18 dph, while alkaline phosphatase activity peaked at 21 dph. Based on these findings, 18 dph was identified as the optimal time to initiate the gradual weaning of larvae to pellet feed. In the second experiment, a 60-day feeding trial was conducted using 27-day-old weaned larvae (0.23 ± 0.03&#xa0;g and 2.42 ± 0.12&#xa0;cm) to evaluate the effects of dietary taurine supplementation. Five experimental diets were formulated with graded levels of taurine: 0&#xa0;g/kg (control), 5&#xa0;g/kg (T1), 10&#xa0;g/kg (T2), 15&#xa0;g/kg (T3) and 20&#xa0;g/kg (T4). Growth and survival significantly (<i>P</i> &lt; 0.05) improved up to T3, with 90% survival in T2 and T3. Antioxidant enzyme activity was highest at T4. Taurine supplementation significantly (<i>P</i> &lt; 0.05) increased haemoglobin, haematocrit and WBCs in blood and elevated glucose, cholesterol, HDL and LDL in serum, while reducing serum triglycerides and VLDL; no significant changes were observed in serum total protein, albumin, globulin, or RBC indices. These findings indicate that 18 dph is the optimal time to initiate weaning to a formulated diet in <i>C. striata</i> larvae, and the post-weaning dietary taurine requirement for <i>C. striata</i> fry was estimated at 16.31–16.40&#xa0;g/kg feed based on broken-line regression analysis.</p>

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Ontogeny of digestive enzymes for weaning and role of dietary taurine supplementation in growth, survival and physiology of Channa striata juveniles

  • 期刊论文

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  • 发表日期：

    2026年4月9日

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  • Shrinath Vaijanath Gavhane,
  • C. Judith Betsy,
  • I. Kaviyarasi,
  • A. Anix Vivek Santhiya,
  • P. Sivasankar,
  • E. Prabu

摘要

Aquaculture plays a vital role in meeting the growing global demand for high-quality protein, particularly in the context of a rapidly increasing human population. Channa striata is an important aquaculture species due to its high nutritional value, rapid growth and adaptability to diverse environmental conditions. However, the demand for C. striata cannot be met due to the limited availability of its seed, as low larval survival remains a significant challenge in hatchery production. Therefore, the present study aimed at studying the influence of dietary taurine supplementation on the growth and survival of C. striata larvae by understanding the ontogeny of digestive enzyme activity. Hence, the study was conducted as two experiments. In the first experiment, the ontogeny of digestive enzyme activity in C. striata larvae was examined to assess the optimal weaning stage. To facilitate this, larvae were sampled at 3, 6, 9, 12, 15, 18, 21, 25 and 30 days post-hatch (dph). The activities of digestive enzymes such as trypsin, chymotrypsin, leucine aminopeptidase and lipase peaked at 18 dph, while alkaline phosphatase activity peaked at 21 dph. Based on these findings, 18 dph was identified as the optimal time to initiate the gradual weaning of larvae to pellet feed. In the second experiment, a 60-day feeding trial was conducted using 27-day-old weaned larvae (0.23 ± 0.03 g and 2.42 ± 0.12 cm) to evaluate the effects of dietary taurine supplementation. Five experimental diets were formulated with graded levels of taurine: 0 g/kg (control), 5 g/kg (T1), 10 g/kg (T2), 15 g/kg (T3) and 20 g/kg (T4). Growth and survival significantly (P < 0.05) improved up to T3, with 90% survival in T2 and T3. Antioxidant enzyme activity was highest at T4. Taurine supplementation significantly (P < 0.05) increased haemoglobin, haematocrit and WBCs in blood and elevated glucose, cholesterol, HDL and LDL in serum, while reducing serum triglycerides and VLDL; no significant changes were observed in serum total protein, albumin, globulin, or RBC indices. These findings indicate that 18 dph is the optimal time to initiate weaning to a formulated diet in C. striata larvae, and the post-weaning dietary taurine requirement for C. striata fry was estimated at 16.31–16.40 g/kg feed based on broken-line regression analysis.