Pre-weaning growth of gilt and sow progeny is not improved by feeding conjugated linoleic acid and medium chain fatty acids during gestation

Gilt progeny (GP) are generally recognised as having reduced growth performance compared to sow progeny (SP; Smits 2011). 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 improves the growth of piglets through increased energy available in colostrum and milk (Azain 1993; Bontempo et al. 2004). This study hypothesised that feeding CLA and (or) MCFA would improve growth rates of both gilt and sow progeny.

A total of 129 primiparous (Parity 0; GILT) and 123 multiparous (Parities 2 and 3; SOW) sows and their piglets (PrimeGro™ Genetics, Corowa, NSW, Australia; 1367 GP and 1546 SP) were involved in the experiment. The experimental design can be found in the companion paper by Craig et al. (2017). Sow bodyweight (SW) and P2 backfat were recorded at entry to the farrowing house and at weaning. Number of piglets born alive (NBA) was recorded and individual piglet bodyweights were recorded within 24 h of birth (PW_d0) and at 21 days of age (PW_d21). Variables were analysed as a linear mixed model using the MIXED procedure of SPSS (v24.0, IBM, Armonk, NY, USA).

Change in P2 (ΔP2) was the only trait for which the diet*parity interaction was significant (P = 0.004). Gilts on the BOTH diet treatment lost more backfat during lactation (–2.4 ± 0.6 mm) compared to CON gilts (–1.4 ± 0.6 mm), whereas all other diet*parity combinations lost less backfat during lactation compared to CON (data not shown). Gilt progeny were lighter than SP at PW_d0 (1.39 v. 1.56 ± 0.02 kg, respectively; P < 0.001) and PW_d21 (5.10 v. 6.27 ± 0.07 kg, respectively; P < 0.001), with a lower ADG in this period (P < 0.05) than their SP counterparts (Table 1). There was no effect of diet on PW_d0 or PW_d21 (P ≥ 0.10), although feeding CLA resulted in reduced body fat loss in gilts and sows (P < 0.10) and a reduction in NBA (P < 0.05; Table 1).

Table 1.  Effects of feeding different lipid sources in late gestation and lactation on gilt and sow reproductive performance and gilt and sow progeny growth parameters

The present study confirms numerous other investigations showing that GP are born lighter and grow slower than SP in the pre-weaning period. However, feeding CLA and (or) MCFA in late gestation and lactation at the current levels did not improve pre-weaning growth of sow or gilt progeny.