Effects of dietary electrolyte balance on the performance, plasma biochemistry parameters and immunoglobulin of sows during late gestation and lactation

Abstract

An experiment was conducted to investigate the effects of dietary electrolyte balance (dEB) on the performance, urine pH, plasma biochemistry parameters, milk composition and immunoglobulin of sows during late gestation and lactation. Forty-eight sows (Landrace×Large white, mean parity 4.1±1.75) were randomly allocated to four dietary treatments, with twelve replicates per treatment and one sow per replicate according to body weight and parity number. The dietary treatments were with dEB values of −100, 0, 162 (control group), and 300mEq/kg from day 90 of gestation to farrowing, transitioning to −100, 0, 198 (control group), and 300mEq/kg dEB, respectively, throughout the subsequent 21 days of lactation. Dietary electrolyte balance values were obtained by manipulating dietary sodium (Na) and chloride (Cl) levels. Calcium (Ca) and phosphorus (P) concentrations were held constant across experimental diets. Blood and urine samples were collected on day 107 of gestation, day of farrowing and weaning (day 21 of lactation). The colostrum and milk samples were obtained on day 0 and day 14 of lactation, respectively. The results showed that average daily feed intake (ADFI) of lactating sows was lower in sows fed a –100mEq/kg diet compared with the other three groups (P<0.05) and other parameters of the sow or litter performance were not different (P>0.05) among dietary treatments. Urine pH values were lower (P<0.05) in sows fed −100 and 0mEq/kg diets compared with the control and 300mEq/kg group, and urine pH of the control group was lower (P<0.05) than that of 300mEq/kg group at all sample periods. Additionally, the pH of the urine was also lower in sows fed −100mEq/kg diet compared with the 0mEq/kg group at the day of weaning (P<0.05). Plasma Cl and Mg concentrations were higher in sows fed −100 or 0mEq/kg diet compared with the control group (P<0.05) at all measurement stages. No differences were observed among dietary treatments in plasma Ca, P concentrations (P>0.05). The percentages of protein, lactose and fat in the colostrum and milk were similar among dietary treatments (P>0.05). The immunoglobulin in plasma, colostrum and milk was higher in sows fed −100 or 0mEq/kg diet compared with the control group (P<0.05). In conclusion, changing dEB during late gestation and lactation did not affect sow or litter performance; or the percentages of protein, lactose, or fat in either colostrum or milk. Decreasing dEB increased plasma Cl and Mg concentrations and enhanced immunoglobulin in plasma, colostrum and milk and reduced urine pH, while, ADFI of lactating sows was lower in sows fed −100mEq/kg diet compared with the other three groups.