Food waste products in diets for growing-finishing pigs: Effect on growth performance, carcass characteristics and meat quality

Forty-eight cross-bred [(Norwegian Landrace x Yorkshire) x (Norwegian Landrace x Duroc)] growing-finishing pigs (average 28.3 kg initial body weight and 104.7 kg final weight) were used to study the effect of adding food waste products (FWP) in diets. The treatments were comprised of six levels of FWP (0, 20, 40, 60, 80 and 100% of net energy), in combination with a barley-soybean diet. The FWP consisted of food leftovers, waste from food-processing plants, bakery waste, dairy waste and blood. The chemical composition of FWP averaged 214 g kg(-1) dry matter, 49 g kg(-1) crude protein, 33 g kg(-1) crude fat, 5 g kg(-1) crude fibre, 115 g kg(-1) N-free extracts and 12 g kg(-1) ash. Increasing dietary levels of FWP reduced (linear, P < 0.001) average daily intake of feed on a dry matter basis (ADFI), and ADFI was significantly lower when pigs were fed the diets with 60% or more of net energy as FWP. Increasing dietary levels of FWP reduced (linear, P < 0.01) the fat firmness and lightness (L* values) of both backfat and loin meat. The proportion of saturated fatty acid in backfat decreased (linear, P < 0.001), while the proportion of polyunsaturated fatty acids increased (quadratic, P < 0.05). The sensory quality of loin muscle was not affected by dietary treatment. To conclude, FWP could be used at moderate levels for growing-finishing pigs without negatively affecting growth performance, carcass characteristics or meat quality.