This study aimed to investigate the effect of soaking dried cashew nut testa ( DCNT) in distilled water on tannin removal. Distilled water was used at a 1:10 (w/v) ratio for 0, 24, and 48 h. Soaking DCNT in distilled water for 24 h reduced tannin concentration in DCNT by 26.4% ( quadratic, P<0.01) . The soaked and unsoaked DCNT were then used for the next experiment. A total of 24 LYD barrows (initial average BW of 82.1 kgs) were used to determine the effect of DCNT on nutrient digestibility and gut morphology in finishing pigs. The pigs were randomly allotted to 4 treatments using a randomized complete block design with 6 pigs per treatment. The treatments were: 1) corn-soybean meal (SBM) diet with no DCNT, 2) corn-SBM diet with 5% unsoaked DCNT, 3) 5% unsoaked DCNT with added fat, and 4) 5% soaked DCNT. All diets included 0.30% Cr2O3 to serve as an inert marker. The results revealed that the unsoaked DCNT diet had reduced apparent total tract digestibility (ATTD) of crude protein (CP), ether extract (EE), and neutral detergent fiber (NDF) than the corn-SBM diet (P<0.05). However, pigs fed the soaked DCNT diet had greater ATTD of CP and EE compared with those on the unsoaked DCNT diet (P<0.05). There were no significant differences in gut characteristics of finishing pigs fed corn-SBM or DCNT diets. In conclusion, feeding 5% DCNT to finishing pigs reduces nutrient digestibility without affecting gut morphology. Soaking DCNT in distilled water for 24 h can reduce tannin concentration and mitigate its effects on nutrient digestibility.
