Dietary lysine and protein for organic grower-finishing pigs

Summary in the original language of the document

The objective of the study was to determine the physiologically optimal supply of standardized ileal digestibility (SID) of lysine for organic growing-finishing pigs. In total, 150 pigs (LY-TN70 x Danbred-Duroc) were included in the experiment from 31 kg (± 4.3 kg) until slaughter at 112 kg (± 11.0 kg). Initially, pigs were distributed according to BW and sex in 15 pens with 10 pigs in each. Pigs were allotted to five different treatments with increasing SID lysine content of 6.1, 6.5, 6.9, 7.3, and 7.7, g/kg, SID CP increased accordingly. The AA ratio relative to lysine and physiological energy in diets remained constant across dietary treatments. Pigs were fed ad libitum with grass clover silage (GCS). Feed and GCS intake for each pen was recorded daily. Pigs were weighed and blood samples were taken initially and at slaughter. At slaughter, hot carcass weight and meat percent were measured. Data were analyzed using the MIXED procedure of SAS. Linear and quadratic effects of dietary treatments were tested. P-values were adjusted using a Tukey test, to account for multiple comparisons. Increased dietary SID lysine did not affect pen average daily feed intake (ADFI; P = 0.90), pen GCS intake (P = 0.94), pig average daily gain (ADG; P = 0.76), pen feed conversion ratio (FCR; P = 0.12), days to slaughter (P = 0.75), nor hot carcass weight (P= 0.61). Pen FCR tended to decrease linearly (P = 0.05), with increasing dietary SID lysine (2.76 to 2.64 kg feed/kg gain), whereas meat percent increased linearly (P = 0.01) with increasing dietary SID lysine (58.6 to 59.8%). In conclusion, diets for organic grower-finisher pigs could be reduced to 6.1 g SID lysine/kg feed without affecting ADG and ADFI, however, FCR and meat percent may be compromised.