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Complexity of the weaning diet has been considered as a key factor to maximize pig growth immediately after weaning. Consequently, prestarter diets for pigs are based generally on high quality ingredients. These high quality ingredients are believed to increase palatability, feed intake, nutrient digestibility and growth performance at expenses of cost. Thus, the inclusion of moderate amounts of selected high quality ingredients such as heat processed maize, fish meal (FM) and lactose (LAC) is a common practice in starter feeds in commercial pig operations. However, the benefits of this feeding practice on pig performance have not been substantiated. The effect of diet complexity on coefficient of total tract apparent digestibility (CTTAD) and growth performance was studied in piglets from 21 to 62 d of age. There were five experimental prestarter diets (21–41 d of age) with similar net energy and total indispensable amino acids content. The negative control diet contained 400 g raw maize, 40 g FM and 70 g LAC/kg and the positive control diet contained 400 g cooked maize, 100 g FM and 140 g LAC/kg. The other three diets were similar to the positive control diet but the cooked maize was substituted by raw maize or contained 40 g FM/kg or 70 g LAC/kg, respectively. Each treatment was replicated six times (six pigs per pen). For the starter period (42–62 d of age), half of the pens of each of the prestarter treatments was sorted into two groups and fed either a standard soybean meal–raw maize–lard diet or a diet with similar nutrient profile that included 200 g cooked maize, 50 g FM, 13 g LAC, 20 g soy protein concentrate and 10 g soybean oil/kg in substitution of lower cost ingredients.
Dietary treatment did not affect piglet performance at any age, but incidence of diarrhea during the prestarter period was higher in piglets fed the negative control diet than in piglets fed any of the other diets (P < 0.05). At 30 d of age, the CTTAD of organic matter and gross energy were lower (P < 0.001) for pigs fed the negative control diet than for pigs fed the other diets, but that of crude protein was not affected. At 50 d of age, dietary treatment did not affect the CTTAD of any dietary component.
It is concluded that the use of high levels of high quality ingredients in the diet did not improve growth performance of piglets at any age. From 21 to 41 d of age, the incidence of diarrhea was reduced and the CTTAD of dietary components was increased when the more complex diets were fed. The inclusion of high levels of high quality ingredients in the diet to maximize performance of young pigs might not be justified under all circumstances.
JD Berrocoso, MP Serrano, L Cámara, PG Rebollar and GG Mateos, 2012. Influence of diet complexity on productive performance and nutrient digestibility of weanling pigs. Animal Feed Science and Technology, 171: 214-222.