Pasta by-product as alternative source of starch in diets for finishing pigs

Corn is the most cereal grain used in heavy pig diets. However, high level of corn in diets might yield yellow-coloured ham with soft subcutaneous fats prone to oxidation. The study evaluated the effect of pasta by-product (Pbp) as alternative starch source to corn in diets for finishing pig on growth performance and carcass characteristics. 144 Italian Duroc¥PIC pigs (72 females (F) and 72 castrated males (CM); BW: 103±3kg) were randomly allotted to 1 of 4 dietary treatments (0, 30, 60, 80% Pbp inclusion) for 91 days in a completely randomized design with a 2x4 factorial arrangement. There were 6 pens per treatment (3 F and 3 CM). Diets were: corn-based diet (CTR); T1: 30% of Pbp; T2: 60% of Pbp; T3: 80% of Pbp. The diets were formulated according to requirements, iso-nutritive and pelleted. The feed intake was recorded daily and average daily gain (ADG), average daily feed intake (ADFI,) and gain to feed ratio (G:F) were obtained. The carcasses and trimmed thighs were weighed at slaughter and yields calculated. The thicknesses of the back fat and Longissimus thoracis et lumborum muscle (LTL) were recorded and the carcass lean percentage estimated. The pH was measured at 45 min and 24 h post mortem on Biceps femoris on cooled thighs. Pen was the experimental unit and gender and Pbp were considered fixed effects. There were no Pbp ¥ sex interactions. Pigs fed Pbp had greater (linear, P<0.05) ADFI than pigs fed the CTR diet. Nevertheless, no differences were detected on final BW, ADG and G:F ratio. The carcass weight and dressing percentage were higher (P<0.05) in CM compared with F (131 vs. 128kg and 78.7 vs. 76.8%, respectively) and there was a quadratic effect of Pbp (126, 132, 130, 130kg for carcass weight and 76.1, 80, 78, 76.8% for dressing percentage, respectively for CTR, T1, T2 and T3). Females had lower (P<0.05) pH measured on Biceps femoris at 45 min post mortem (6.07 vs. 6.1) than CM and there was an effect (quadratic, P<0.05) of Pbp (6.17, 6.06, 6.02 and 6.04, respectively for CTR, T1, T2 and T3). The trimmed thigh weight were similar across gender and Pbp, however the yield was lower (P<0.05) in CM compared with F (22.0 vs. 22.7%) with a quadratic effect (P<0.05) of Pbp (22.7, 21.7, 22.4 and 22.7%, respectively for CTR, T1, T2 and T3). Increasing Pbp linearly reduced (P<0.05) the LTL thickness and carcass lean percentage. The Pbp did not affect animal performance and could partially replace corn in diets for finishing pigs.