The effect of Japanese eel as a main ingredient on hair condition, antioxidant ability, apparent total tract digestibility (ATTD) and body weight gain in cat food

Yilin Yuan¹Leilei Zhu¹Xuan Cai^2*Hui Mao²Tingting Wang³Shengqing Tao³Jiayu Bao³Chengyin Liu⁴Jie Feng^1*

• ¹Zhejiang University, Hangzhou, Zhejiang Province, China
• ²Shanghai Academy of Agricultural Sciences, Shanghai, China
• ³Hangzhou PETISALL Biotechnology Co., Ltd, Hangzhou, China
• ⁴PETIDEAL Pet Food (Luohe) Co., Ltd, Luohe, China

This study aims to evaluate the impact of Japanese eel (Anguilla japonica) as a primary ingredient in cat food on hair condition, antioxidant ability, apparent total tract digestibility (ATTD), and body weight gain in adult cats. Twenty-four healthy adult cats were randomly divided into three dietary groups: a 0% eel group (C), a 14% eel group (T1), and a 40% eel group (T2). Over a 56-day period, hair coat condition, ATTD, antioxidant indices, and body weight were monitored. The results indicated an improvement in hair luster and softness in the high eel group. By day 56, the 40% eel group exhibited a significant improvement in hair luster (3.0 vs. 2.4 in control, P< 0.05) and softness (3.0 vs. 2.2 in control, P< 0.05). Scanning Electron Microscopy (SEM) analysis confirmed a significant reduction in hair scale thickness in the 14% (39.36% reduction) and 40% eel groups (46.80% reduction) compared to the control (P < 0.05). The ATTD of calcium was significantly higher in both eel groups (71.3% in T1 and 74.1% in T2 vs. 62.8% in control, P< 0.05), while there were no significant differences in crude fat and protein digestibility (P> 0.05).Serum antioxidant capacity was notably enhanced in the 14% eel group, with a 23% increase in total antioxidant capacity (T-AOC) and a 15% increase in superoxide dismutase (SOD) activity compared to the control (P< 0.05). Additionally, glutathione (GSH) content was higher, and malondialdehyde (MDA) levels were lower in the eel groups, although these differences were not statistically significant (P> 0.05). Notably, body weight gain showed a slight downward trend in the eel groups, with the average daily gain being 2.1 g/day in T2 versus 2.4 g/day in the control group, though this was not significant (P> 0.05). Fecal scores remained consistent across all groups, indicating no adverse effects on fecal quality (P> 0.05). These findings suggest that incorporating eel into cat food can enhance hair coat condition and antioxidant capacity without adverse effects on body weight or fecal quality. Therefore, it is recommended to include 14% level for optimal benefits.