RESUMEN
1. A total of 720 female broiler chicks was used to test the effects of 4 dietary concentrations of a Chinese herbal medicine (CHM) formulation (0.25, 0.5, 1 and 2g/kg), as an alternative for virginiamycin (VRG), on growth performance in broilers. 2. A total of 72 birds from non-supplemented, VRG and 0.5 g/kg CHM groups was selected and killed and the relative weights of the intestinal segments were assessed. 3. The CHM dietary treatments produced increased body weight gain at 7 to 21 d of age but not at 21 to 28 d of age compared with the non-supplemented and VRG groups. The CHM groups had a higher feed intake and a higher feed conversion ratio (FCR) than the VRG group between 21 and 28 d. 4. The dissection results showed that the liver colour of the birds in the CHM group varied less between animals than that of the VRG and the non-supplemented groups. Neither CHM nor VRG had any significant effects on either liver or intestinal tract weights. 5. It was concluded that the birds of the CHM group had better growth performance from d 7 to 21 but not thereafter. Further experiments are needed to elucidate the mechanisms underlying enhanced growth performance by CHM in broilers.
Asunto(s)
Peso Corporal/efectos de los fármacos , Pollos/crecimiento & desarrollo , Medicamentos Herbarios Chinos/farmacología , Animales , Antibacterianos/farmacología , Ingestión de Alimentos/efectos de los fármacos , Femenino , Intestinos/efectos de los fármacos , Hígado/efectos de los fármacos , Tamaño de los Órganos/efectos de los fármacos , Virginiamicina/farmacologíaRESUMEN
In a field trial conducted on a commercial swine farm, lean-genotype sows (n = 485) were fed diets containing 0 or 10% supplemental fat as either medium-chain triglyceride or choice white grease from d 90 of gestation until weaning (15.5 d). Effects on standard sow and litter production traits were examined together with assessment of sow body condition using live ultrasound. Daily feed intake during lactation was 10% higher in sows consuming diets without added fat (7.2 vs 6.5 kg; P < 0.01); however, lactation ME (23.9 Mcal/d) and digestible lysine (54 g/d) intakes were unaffected (P > 0.10). Sows supplemented with fat were 4 kg heavier on d 109 of gestation (220 vs 224 kg; P < or = 0.01), 1 d after farrowing (210 vs 214 kg; P < or = 0.01), and at weaning (210 vs 214 kg; P < or = 0.01). Expressed as overall gain, this amounted to a 23% increase (0.66 vs 0.86 kg/d; P < or = 0.01) and was accompanied by a 49% increase in backfat (0.82 vs 1.68 mm; P < or = 0.03) from d 90 to farrowing. Changes in sow weight (-0.01 kg/d) and backfat (+4.2 mm) over lactation were minimal and were not affected by fat supplementation (P > or = 0.10). Longissimus muscle area at weaning was slightly greater (44.96 vs 46.2 cm2) in sows consuming fat than in control sows (P < or = 0.05), but changes in longissimus muscle area were not significant from d 90 to weaning (P > or = 0.10). Gestation length, pigs born alive, average birth weight, survival (d 3 to weaning), and days to estrus were not affected by diet (P > 0.10). However, supplemental fat increased pig ADG (192 vs 203 g/d; P < 0.01) and average pig weaning weight (4.3 vs 4.5 kg) at 15.5 d (P < or = 0.02). No differences between the two fat sources were detected. This large-scale study demonstrated that supplemental fat during gestation and lactation effectively improved sow condition and improved suckling pig performance without affecting energy intake during lactation, implying improved efficiency of sow energy utilization.