Nutritional value of whey permeate and egg products in ileal-cannulated grower pigs

• Whole egg had greater lysine digestibility and net energy value than the egg–whey permeate blends.
• The proportion of whole egg (300 vs. 400 g/kg) in the whole egg–whey permeate blend did not affect lysine digestibility.
• The blend with 400 g whole egg/kg had greater net energy value than blend with 300 g whole egg/kg.

Eggs not destined for human consumption from egg-breaking plants have high amino acid (AA) and fat content. In contrast, whey permeate (WP), co-product from dairy industry, has high lactose content. Thus, blends of eggs and WP can be sources of protein and energy in swine diets; however, limited information exists about the nutritional value of such blends. A study was conducted to determine standardized ileal digestibility (SID) coefficient of AA and calculated net energy (NE) value for dried whole egg (EGG) and 2 blends of WP and EGG (700 g WP/kg and 300 g EGG/kg, 7030PE; and 600 g WP/kg and 400 g EGG/kg, 6040PE). Eight ileal-cannulated barrows (35.1 kg body weight) were fed 4 diets in a replicated 4 × 4 Latin square design. The diets were a basal diet including a pre-grower feed and corn starch, and this basal diet with energy- and AA-yielding ingredients replaced with 300 g EGG/kg or 400 g/kg of either 7030PE or 6040PE. Energy and nutrient digestibility in the test products was determined by difference method. The SID coefficient of AA was calculated using published values for basal ileal endogenous AA losses. On dry matter basis, EGG, 7030PE and 6040PE contained 489, 186 and 214 g crude protein/kg; 36.0, 9.80 and 11.7 lysine g/kg; and 393, 88.9 and 124 g ether extract/kg, respectively. The SID coefficient of lysine was greater (P < 0.05) for EGG (0.869) than for 7030PE (0.736) or 6040PE (0.708). However, EGG had lower (P < 0.05) SID of arginine, histidine, isoleucine and phenylalanine than 7030PE or 6040PE. The 7030PE and 6040PE did not differ in apparent total tract gross energy digestibility and SID coefficient of all AA. The NE (on dry matter basis) for EGG (20.2 MJ/kg) was greater (P < 0.05) than that for 7030PE (14.9 MJ/kg), which was lower (P < 0.05) than that of 6040PE (16.0 MJ/kg). In conclusion, the proportion of EGG (30 vs. 40%) in the EGG–WP blend did not affect the digestibility of gross energy and of most AA; however, the NE value was greater for the blend with 400 g EGG/kg due to the high fat content in EGG. EGG–WP blends had lower lysine digestibility than EGG, implying that lysine was partly damaged by the blending and drying process. Nonetheless, the EGG–WP blends had high AA digestibility and NE values; hence, these blends can be included in swine diets as source of AA and energy.