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Nucleotide supplementation in the diet of farrowing sows and its effect on milk quality, litter weight gain, and mortality
It is not yet understood whether increased nucleotides in sow milk are a response to a requirement of piglets or are part of the composition of milk, as it naturally occurs during lactation. However, exogenous nucleotide supplementation is able to further increase these levels. The objective of this study was to evaluate effects of nucleotide supplementation in farrowing sows diets on performance, RNA concentration in milk, and piglet litter performance. The nucleotides were derived from a yeast source containing hydrolyzed RNA (free nucleotides/nucleosides). The trial was conducted with 80 sows (Agroceres PIC®) distributed in a completely randomized design (by parity order, avg. 3.7/treatment), with 4 treatments (0, 4, 8, and 12kg/MT of yeast or 0, 0.24, 0.48 and 0.72kg/MT of free nucleotides/nucleosides) and 20 replications of 1 sow in each. The sows were fed experimental diets starting 3 days before farrowing, until weaning of piglets at 21 days of age. The number of piglets per sow (10.48±0.26) and piglet weight (1.70±0.04kg) was equalized at birth. The sow parameters were weight after farrowing (WF,kg), weight after weaning (WW,kg), weight loss (WL,%), and feed intake (FI,kg). The number of weaned piglets (NWP), piglet weight at weaning (PWW,kg), litter weight at weaning (LWW,kg), litter weight gain (LWG,kg), mortality (MORT,%), and milk production (MP,kg; 1kg of piglet weight=4kg of milk) were measured. Samples of colostrum and milk (11, 20 days of lactation) were collected for laboratory analysis of RNA (mg/ml milk). The data were analyzed using the GLM (SAS), and means were compared by Tukey’s test (P=0.10). Nucleotide supplementation in the diet of farrowing sows resulted in no difference (P>0.10) in WF, WW, WL, or FI. The piglets from sows fed diets supplemented with nucleotides had improved (P<0.10) NWP, LWW, LWG, MORT, and MP compared with unsupplemented diets. There were no differences (P>0.10) between treatments in PWW. In general, the 8kg/MT and 12kg/MT levels showed best piglet performance results (6% and 4.5% higher LWG than control group) and lower MORT (41.7% and 53.5% lower than control group). Nucleotide supplementation gave no significant response (P>0.10) in total RNA in colostrums, but the amount of RNA present in milk at 11 and 20 days of lactation significantly increased (P<0.10). This study demonstrated that supplementation of nucleotides to farrowing sows had a positive carryover effect on milk quality which, consequently, increased the litter weight gain and the number of weaned piglets (+3.5%).
Keywords: piglet, performance, RNA