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Factors such as the genetic background of the pigs, dietary net energy (NE), and NE to crude protein (CP) ratio of the diet, affect growth performance, carcass and meat quality. The purpose of this research was to investigate the influence of net energy (NE) concentration of diets with similar CP content and indispensable AA to NE ratio, on growth performance and carcass and meat quality traits of crossbred from Landrace × Large White females and two Pietrain sire lines (A and B) slaughtered at 160 d of age. At 95 d of age, pigs were weighed individually and allotted at random, within each genetic background (49.7 vs. 46.3 kg BW, for the A and B crossbreds, respectively), to their corresponding experimental diet. Treatments consisted in four diets that differed in the NE content. The feeding program consisted of two periods with a growing diet supplied from 95 to 133 d of age (16% of CP content) and a fattening diet supplied from 133 d to the end of the experiment (160 d of age) (15.4% of CP content). All diets were based on cereals, rapeseed meal, and soybean meal.
Within each of the two feeding periods, the NE content of the diets varied according to treatment (9.8, 10.0, 10.3, and 10.5 MJ/kg) however the AA:NE ratio (g/MJ) of all diets was maintained constant. In fact, the lysine to NE ratio was 1.04 in the diets fed from 95 to 133 d of age (48 to 81.3 kg BW) and 0.97 in those fed from133 to 160 d of age (81.3 to 103.8 kg BW). Feed intake (FI) decreased linearly and feed efficiency improved linearly as the NE content of the diet increased. Crossbreds from A had greater FI and average daily gain (ADG) but were less efficient than crossbreds from B. B crossbreds were leaner and had higher shoulder yield and less fat at m. Gluteus medius than carcasses from A crossbreds. Crossbreds from A sires have greater ADG and fatter carcasses than crossbreds from B sires, but both crossbreds responded in similar way to increases in energy concentration of the feeds.
In summary, an increase in the NE concentration of the diet improved feed efficiency but did not affect ADG. Crossbreeds from A sires grew faster and had fatter carcasses than crossbreds from B sires.
Cámara, L., Berrocoso, J. D., Coma, J., López-Bote, C. J., and Mateos, G. G. (2016). Growth performance and carcass quality of crossbreds pigs from two Pietrain sire lines fed isoproteic diets varying in energy concentration. Meat science, 114, 69-74. http://dx.doi.org/10.1016/j.meatsci.2015.12.013
