Growth Performance, Digestibility and Gut Morphology of Grower Pigs fed Diets Substituted with Watermelon Waste

This study was carried out to assess the performance of growing pigs fed diets substituted with watermelon (Citrullus lanatus) waste (WMW). Thirty-six crossbred (Landrace×Large White) pigs were randomly allotted to four dietary treatments in a completely randomised design. The control (CON) group was fed a ration containing 40% cassava peel meal and 60% concentrate, while the other three groups were fed the same diet but with 20 (WM-20), 40 (WM-40) and 60 (WM-60) parts of the concentrate component substituted with watermelon waste on an equivalence basis. The experiment lasted for 8 weeks. Data were collected on performance indices, nutrient digestibility, and gut morphology. Pigs on CON diet had highest (P<0.05) final body weight (31.70 kg) while least body weight of 21.76 kg was observed for pigs on WM-60. Weekly feed intake was highest (P<0.05) in pigs fed WM-20 (9.51 kg) but not different from pigs fed CON (9.15 kg) and WM-40 (9.16 kg) while pigs on WM-60 had the least intake of 7.75 kg. Feed conversion ratio increased (P<0.05) with increasing levels of WMW with pigs in CON having least FCR (3.51) while it was highest for WM-60 (5.11). Crude protein digestibility was highest (P<0.05) in pigs on WM-40 (71.48) and WM-60 (71.48) while fat (40.91) and crude fibre (21.13) digestibility were least in WM-60, compared to other treatments. Morphological measurements of ileum and jejunum were not significantly (P>0.05) affected by increasing levels of WMW except for the crypt depth in ileum and jejunum which was higher in CON (349.60 μm) and WM-60 (216.65 μm). In conclusion, it can be said that watermelon waste can be used as a substitute for concentrate at 20% level in diets of growing pigs without any detrimental effect on growth.