Utilization of Ensiled Sweet Potato ( Ipomoea batatas (L.) Lam.) Leaves as a Protein Supplement in Diets for Growing Pigs L.VanAn 1 ,T.T.T.Hong 1 ,B.Ogle 2 andJ.E.Lindberg 2 * 1 Hue Universityof Agricultureand Forestry, Hue City,Vietnam; 2 Departmentof Animal Nutrition and Management, Swedish Universityof Agricultural Sciences, P.O. Box 7024, 750 07 Uppsala, Sweden *Correspondence:E-mail:Jan-eric.Lindberg@huv.slu.se Van An, L., Hong,T.T.T., Ogle, B. and Lindberg, J.E., 2005. Utilization of ensiled sweet potato ( Ipomoea batatas (L.) Lam.) leaves as a protein supplement in diets for growing pigs. Tropical Animal Health and Production, 37(1),77^88 ABSTRACT Four diets were formulated with protein from ¢shmeal (FM), groundnut cake (GC), ensiled sweet potato ( Ipomoea batatas L. (Lam.)) leaves (SP) or ensiled sweet potato leaves with lysine (SPL). In experiment 1, 24 crossbred (Large White6Mong Cai) growing pigs were allocated randomly by sex intofourgroupsofsixpigsandgivenoneoffourdiets.Experiment2wasconductedusing16crossbred pigs (LargeWhite6Mong Cai) at four farms. On each farm, pigs were allocated to two experimental groups.OnegroupwasfedtheFMdietandtheothergrouptheSPLdiet.Inexperiment1,thedailylive weightgains(DLWG)weresigni¢cantlyhigher( p50.05)fortheFMandSPLtreatments(542and536 g/day, respectively) than for the GC and SP treatments (464 and 482 g/day, respectively). Feed intake was highest (2.0 kg/day) for the SPLand lowest (1.7 kg/day) for the GC treatment ( p50.05)andfeed conversion ratio (FCR) was highest (3.8 kg/kg gain) for SP and lowest (3.5 kg/kg gain) for FM ( p50.05).There were no signi¢cant di¡erences for carcase measurements among diets ( p40.05).The feedcostperkgliveweightgainwaslowestfortheSPandSPLdietscomparedtotheFMandGCdiets. The results of experiment 2 show that there were no signi¢cant di¡erences in feed intake, DLWG and FCR between the two diets ( p40.05). In conclusion, sweet potato leaves can replace ¢shmeal and groundnutcakeintraditionalVietnamesedietsforgrowingpigs. Keywords: carcase,ensiling,lysine,performance,pigs,sweetpotatoleaves. Abbreviations: DLWG, daily live weight gain; FCR, feed conversion ratio; FM, ¢shmeal; GC, groundnut cake; ME, metabolizable energy; SP, sweet potato; SPL, sweet potato leaves and lysine; VND,VietnameseDong INTRODUCTION Indevelopingcountries,pigproductionnotonlyplaysanimportantroleingenerating income but also provides manure for crops. In the rural areas of Vietnam the main source of cash for farmers is pig production, normally with 3^4 pigs kept per household. Pig production is based on locally available feed resources and traditional diets include cassava root meal, rice bran and vegetables. These diets have a low protein content, so the farmers often add ¢shmeal or groundnut cake as a protein TropicalAnimalHealthandProduction,37(2005)77^88 # 2005Springer.PrintedintheNetherlands 77