# Hydrolysed Feather Meal Inclusion in Low Fishmeal Diets for Whiteleg Shrimp (Penaeus vannamei)

## TL;DR

This study shows that hydrolysed feather meal can be added up to 5% in shrimp feed without harming growth or health, offering a sustainable protein alternative.

## Contribution

The study demonstrates the safe inclusion of up to 5% hydrolysed feather meal in low-fishmeal diets for whiteleg shrimp.

## Key findings

- Growth performance and feed conversion ratio were unaffected by hydrolysed feather meal inclusion.
- Digestive enzymes like trypsin and chymotrypsin showed mild increases at low inclusion levels.
- Muscle composition remained stable, with only a modest increase in ether extract.

## Abstract

The global transition toward low‐fishmeal formulations has intensified the search for sustainable and digestible protein alternatives in shrimp aquaculture. Enzymatically hydrolysed feather meal (HFM) represents a promising high‐protein ingredient with enhanced digestibility and bioactive potential. This study evaluated the effects of graded HFM inclusion (0%–5%) on growth performance, digestive enzyme activity, antioxidant status, and muscle composition of Penaeus vannamei juveniles. Five isonitrogenous (40.2 ± 1.9% crude protein) and isolipidic (12.3 ± 1.4% crude lipids) diets were formulated with 0%, 1.25%, 2.5%, 3.75%, and 5.0% HFM, replacing part of the soybean meal while maintaining a constant fishmeal inclusion (6%). A total of 100 shrimp (initial weight 1.2 ± 0.1 g; initial length 4.3 ± 0.3 cm) were randomly distributed into 20 tanks (4 tanks per diet; 20 shrimp per diet) and reared for 50 days under controlled clear‐water conditions. Growth performance, feed efficiency, digestive and antioxidant enzyme activities, and abdominal muscle composition were analysed using one‐way ANOVA and polynomial regressions. Growth and feed conversion ratio were unaffected by HFM inclusion (p > 0.05). Lipase, cellulase, and carbohydrate‐digesting enzymes remained stable, while trypsin and chymotrypsin showed a mild increase at 1.25%–2.5% inclusion. Glutathione peroxidase activity tended to increase (p = 0.10), whereas reduced glutathione was significantly lower in all HFM‐fed groups (p < 0.001). Lipid peroxidation (TBARS) and glutathione reductase remained unchanged. Muscle protein and moisture were unaffected, while ether extract showed a modest but significant increase (p < 0.001). In conclusion, enzymatically HFM can be safely incorporated up to 5% in low‐fishmeal diets for P. vannamei without impairing growth, digestive function, antioxidant defence, or flesh composition, supporting its potential as a sustainable ingredient for modern shrimp feeds.