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), rang ing in live weight from 35-160 kg, were homogeneously divided into three gr oups fed as follows. T1, control group, in which animals received a 'tradit ional diet based on cereals and soybean meal; T2, in which plain pressed be et pulp silage (PPBPS) partially replaced barley (for 15 % on a dry matter basis); and T3, in which molassed pressed beet pulp silage (MPBPS) substitu ted barley at the same rate as in group T2. The animals were fed at the rat e 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 th e PPBPS diet showed a significant (P < 0.05) improvement of daily weight ga in. No differences (P > 0.05) concerning FCR were observed between groups, although energy conversion was improved for pigs receiving both types of th e by-product. Pigs were slaughtered at around 160 kg live weight. The main qualitative parameters of carcasses, meat (pH and colour) and fat (fatty ac id composition) were collected. Pigs receiving pressed beet pulp showed a s ignificant (P < 0.05) improvement of the weight of the gastrointestinal tra ct, inducing a slight reduction of the dressing out percentage in compariso n with control animals. Back Fat thickness and muscle percentage did not di ffer 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 a nd 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 rega rd to ham weight loss. Our data indicate that pressed beet pulp silage, eit her 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 fer mentable polysaccharides content, can induct a reduction of feed cost due t o cereals such as barley sparing. ((C) Elsevier / Inra).