Along with the practice of earlier weaning, we have recently adopted the feeding of highly complex nursery diets. These commercial nursery diets contain high levels of spray-dried plasma and whole blood or blood cells. These rendering byproducts are known to be low in methionine. Thus, after lysine, methionine is the second limiting amino acid for weanling pigs in typical nursery diets presently. Although it has become customary to add supplemental methionine to nursery diets, questions remain as to which source of supplemental methionine should be used. Considering the importance of getting weanling pigs consuming dry feed as quickly as possible, and the benefits of weight gain during the nursery period on reducing days to market, it is important to determine if the different commercially available sources of methionine affect diet acceptance.
During the first, third and fifth week following weaning at approximately 21 day of age, pigs were offered a choice between a basal diet (control) or the basal diet supplemented with DL-methionine, liquid methionine or liquids methionine hydroxy analogue (MHA), with or without a flavouring/aromatic agent. Daily feed disappearance was used as an indicator of diet preference.
The diet supplemented with DL-methionine was preferred by pigs over the control diet for the first three days following weaning. Both the DL-methionine and the liquid MHA supplemented diets were preferred by pigs over the control diet for the last three days of the first week of the study. The dietary addition of DL-methionine, liquid methionine or liquid MHA increased the preference of pigs for these diets compared with the basal control diet during the entire third and fifth week. These results indicate no adverse effect of these supplemental methionine sources on the diet preference of nursery pigs.
The dietary addition of the flavouring/aromatic agent used in the present study reduced the preference of pigs for the treatment diets irrespective of the supplemental methionine source.