Effect of Lysine Supplementation and Feeding Frequency on the Gut Morphology and Intestine Histology of African Catfish (clarias Gariepinus)

This study investigated the combined effects of lysine supplementation (F) and feeding frequency (I) on gut morphology and intestinal histology of African catfish (Clarias gariepinus). The objective was to determine the optimal lysine levels, assess the impact of feeding frequency, and evaluate their interaction on gut health and intestine histology.
The experiment was conducted in a recirculating aquaculture system using a 3 × 2 factorial design: three lysine levels (0%, 2%, 4%) and two feeding frequencies (2× and 4× daily), each with three replicates. Eighteen tanks were stocked with 20 juveniles and was fed six experimental diets: D1(T0I2), D2 (T0I4), D3 (T2I2), D4 (T2I4), D5 (T4I4), and D6 (T4I4). At the end of the trial, gut morphology (villus height, width, crypt depth) and histology (goblet cells, epithelial integrity) were analyzed via microscopy following the standard histological techniques and H&E staining.
The results showed significant interaction was observed in villus height (p = 0.0060), with D4 (T2I4) showing the longest villi (1911.49 µm), Histological analysis revealed inflammation and epithelial damage. A dose-dependent pattern of pathology, including atrophy and necrosis, especially in lysine-supplemented groups. Even the control group showed mild inflammation, which was worsened by higher feeding frequency. This study concludes, 2% and 4% lysine supplementation with increased feeding frequency negatively affected gut health without promoting growth. Excess lysine led to intestinal damage, emphasizing the importance of balanced amino acid formulations rather than simply increasing crude protein.
Keyword; lysine supplementation, feeding frequency’s gut morphology, intestine histology
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