Effects of feeding conjugated linoleic acid (CLA) and medium chain fatty acids (MCFA) to gilts and sows on survival of their progeny

Feeding lipid sources such as conjugated linoleic acid (CLA) and medium chain triglycerides or their acids (medium chain fatty acids; MCFA) to the sow in late gestation and lactation has been shown to improve the survival of piglets, in particular those of low birthweight, through increased energy and immunoglobulins available in colostrum and milk (Azain 1993; Bontempo et al. 2004). Gilt progeny (GP) have higher rates of mortality and medication compared to sow progeny (SP; Smits 2011). It was hypothesised that feeding CLA and (or) MCFA would improve survival of both progeny groups, with improvements more pronounced in the lighter, more immunocompromised GP.

A total of 129 primiparous (Parity 0; GILT) and 123 multiparous (Parities 2 and 3; SOW) sows and their piglets (PrimeGro™ Genetics, Corowa, NSW; 1367 GP and 1546 SP) were involved in the experiment. Diets consisted of different sources of dietary lipid: (1) 6% tallow (CON); (2) 2.5% tallow replaced with a commercial CLA product (Lutrell^® Pure; BASF; 50% c-9,t-11 and 50% t-10,c-12 CLA isomers); (3) 0.1% tallow replaced with a commercial MCFA product (Aromabiotic^® Pig, Nuscience, Drongen, Belgium); and (4) equal parts of the CLA and MCFA diets (by weight, i.e. 1.25% CLA, 0.05% MCFA; BOTH). Experimental diets were fed from an average of d 107 of gestation until weaning at d 27 of lactation. Cross-fostering between litters was carried out as per standard production protocols to equalise litter numbers. A serum sample was collected from a subsample of piglets (n = 144) 3 days after birth. A sample of colostrum was collected at birth, and a milk sample was collected on d 21 of lactation from a subsample of sows (n = 68). Serum samples were assayed for immunoglobulin G (IgG) and β-hydroxybutyrate (βHBA) concentrations using commercial kits. Colostrum (IgG_d0) and milk samples (IgG_d21) were assayed for IgG concentration. All piglet mortalities were recorded. Continuous variables were analysed as a linear mixed model using the MIXED procedure of SPSS (v24.0, IBM, Chicago, IL, USA). Mortality was analysed using χ². The diet*parity interaction was not significant for any trait (P ≥ 0.10).

Lower IgG in GP compared to SP (P < 0.05; Table 1) despite similar levels of IgG_d0 and IgG_d21 (P ≥ 0.10) suggests that GP may absorb less IgG through colostrum and milk than SP. Contrary to the current hypothesis, feeding 2.5% CLA or 0.1% MCFA (or a combination of both) in the late gestation and lactation diet did not significantly improve immune status, energy levels or pre-weaning mortality rates in gilt or sow progeny.

Table 1.  Effects of feeding different lipid sources in late gestation and lactation on colostrum, milk and serum metabolites, and pre-weaning mortality in gilt and sow progeny