Increased dietary energy content increases average daily gain and carcass weight in entire male pigs fed ad libitum | L’augmentation de la teneur en énergie de l’aliment, associée à un maintien de l’équilibre avec les acides aminés, permet d’augmenter la vitesse de croissance et le poids de carcasse des porcs mâles entiers alimentés à volonté

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Inglés. Fattening performance and carcass characteristics of crossbred Piétrain x (Large White x Landrace) entire male pigs fed ad libitum with growing-finishing diets formulated either to 9.4 (i.e., NE 9.4) or 9.9 (i.e., NE 9.9) MJ/kg of net energy (NE) were compared. Eight pens of seven pigs per treatment were studied. At 69 days of age, pigs were allocated to diets as a function of body weight (BW) and litter of origin. Average daily feed intake was similar with both diets (2.68 kg/d, P = 0.83); thus, NE intake tended to be higher with the NE 9.9 diet (26.5 vs NE 9.4: 25.2 MJ/d, P = 0.08). With the higher NE, the feed-conversion ratio was significantly lower when expressed in kg/kg (2.35 vs NE 9.4: 2.51, P < 0.01) but not in MJ NE/kg (P = 0.21), as the NE 9.9 pigs had a higher average daily gain (1128 vs NE 9.4: 1060 g/d, P < 0.01). Consequently, they tended to be heavier at slaughter (121.5 vs NE 9.4: 117.6 kg BW, P = 0.09), with a better carcass yield (79.9% vs NE 9.4: 78.8%, P < 0.01). It resulted in heavier NE 9.9 carcasses (97.2 vs NE 9.4: 93.1 kg, P < 0.01), which had thicker G4 backfat (+1.6 mm, P < 0.01) and M4 (+2.3 mm, P = 0.02) and M3 (+1.9 mm, P = 0.06) muscle thicknesses but similar G3 backfat depth than NE 9.4 carcasses did. The carcass leanness determined from these criteria was not influenced by the dietary NE content (mean of 61.4, P = 0.49). These results demonstrate that increasing the dietary NE content from 9.4 to 9.9 MJ/kg, and amino acids accordingly, could help increase energy intake by entire male pigs and may be an interesting solution to stimulate the growth rate when the pork-price context encourages heavier carcasses.

Francés. Les hormones sexuelles sécrétées par le porc mâle entier limitent son appétit : c'est pourquoi la quantité d’énergie ingérée limite la rétention protéique et le gain de poids pendant l'essentiel de l'engraissement.Cette situation est avantageuse en termes d'indice de consommation (IC) ou de teneur en muscle des pièces (TMP) de la carcasse, mais peut poser problème quand la vitesse de croissance (GMQ) n'est pas suffisante pour permettre d'atteindre le poids d'abattage recherché.Hypothèse : augmenter la teneur en énergie de l’aliment permet de stimuler la consommation énergétique et le GMQ des porcs mâles.