A total of 96 non-lean-type (Yorkshire × Landrace) × Duroc gilts and barrows weighing approximately 80 kg were randomly allocated to 24 pens under a 2 (sex) × 3 [diet; 3.4, 3.2, and 3.0 Mcal DE/kg {'high'-, 'medium'-, and 'low'-energy diets (HE, ME, and LE), respectively}] factorial arrangement of treatments. All animals were slaughtered approximately at 115 kg, after which carcass quality traits and grades and physicochemical and sensory characteristics of the loin related to meat quality were analyzed. The ADG and gain:feed were not affected by the sex or dietary treatment, whereas ADFI was greater in the ME vs HE group. Backfat thickness was greater in barrows vs gilts and also in ME and HE vs LE only in barrows. Enumerated carcass marbling and quality grade, which were highly correlated (r=0.56; P<0.01), were greater in barrows vs gilts. Physicochemical characteristics including the color, pH, drip loss and contents of moisture, protein, and fat of fresh loin, as well as sensory characteristics of fresh and cooked loin, were not affected by the sex or dietary treatment, except for shear force for cooked loin which was greater (P<0.05) in LE and ME vs HE. In conclusion, it is thought that ME is comparable to HE in terms of the effect on growth and carcass quality of finishing pigs, but that the relative effect of LE vs ME needs to be further studied.

The aim of the present study was to investigate the effects of partial substitution of an extruded or extruded-pelleted corn product for unprocessed corn of the starter diet on growth performance and incidence of diarrhea in weanling pigs. Seventy-two 21-day-old weanling pigs were allotted to 24 pens and provided ad libitum with one of the four experimental diets for 3 wk in two serial feeding trials during summer beginning from late June. The treatments were a milk product-soy-corn-based control diet containing 25% unprocessed corn and the other three diets only substituted with 12.5% extruded corn Suprex ® , Optigrain ® , an extruded mixture of wheat, rye and durum, or extruded-pelleted corn for an equal percentage of unprocessed corn of the control diet. All diets were supplemented with 100 ppm sulfathiazone, 50 ppm penicillin, and 100 ppm chlortetracycline for preventive medication. The initial and final weights as well as gain : feed were less in the second trial than in the first one (P<0.05). However, effects of the dietary treatments were not detected in any of the performance variables including final weight, ADG, ADFI, and gain : feed, nor were there any interactions between the trial and dietary treatment. In addition, almost all pigs exhibited normal firm feces in both trials and therefore there was no main effect in the fecal consistency score. Results suggest that partial substitution of the thermally processed corn for unprocessed corn of the milk product-corn-soy-based and medicated starter diet has no effect on growth performance or incidence of diarrhea in weanling pigs.

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