The effects of sugar beet pulp silage in the diets for heavy pigs.

Sixty Landrace x Large White pies (30 females and 30 castrated males), ranging in live weight from 35-160 kg, were homogeneously divided into three groups fed as follows. T1, control group, in which animals received a 'traditional diet based on cereals and soybean meal; T2, in which plain pressed beet pulp silage (PPBPS) partially replaced barley (for 15 % on a dry matter basis); and T3, in which molassed pressed beet pulp silage (MPBPS) substituted barley at the same rate as in group T2. The animals were fed at the rate of 9 % of their metabolic live weight up to a maximum of 3.2 kg.pig(-1)d(-1). Pigs were individually weighed at 0, 35, 105 and 182 d of trial. Feed intake was recorded to calculate the feed conversion rate (FCR). Pigs on the PPBPS diet showed a significant (P < 0.05) improvement of daily weight gain. No differences (P > 0.05) concerning FCR were observed between groups, although energy conversion was improved for pigs receiving both types of the by-product. Pigs were slaughtered at around 160 kg live weight. The main qualitative parameters of carcasses, meat (pH and colour) and fat (fatty acid composition) were collected. Pigs receiving pressed beet pulp showed a significant (P < 0.05) improvement of the weight of the gastrointestinal tract, inducing a slight reduction of the dressing out percentage in comparison with control animals. Back Fat thickness and muscle percentage did not differ depending on the diet; these parameters were significantly (P < 0.01) affected only by the sex of the animals. Similarly, the yield of the lean and fatty cuts was not affected by the diets, the significant differences (P < 0.01) being exclusively related to the different hormonal status of the entire females and castrated males. Meat colour and pH were not affected hy the diet as well as ham fat acidic composition. Raw hams were cured over a 13-month period. No differences between the groups were observed with regard to ham weight loss. Our data indicate that pressed beet pulp silage, either molassed or plain, can be profitably used in the diets for heavy pies. The high energy supply of beet pulp. which is related to its non-starch fermentable polysaccharides content, can induct a reduction of feed cost due to cereals such as barley sparing. ((C) Elsevier / Inra).