In the present systematic review and meta-analysis, we evaluated the effects of providing piglets with creep feed during lactation on piglet pre- and post-weaning performance. A total of 20 articles met the inclusion criteria. Creep feeding in lactation improved pre-weaning piglet performance in 46% of the studies selected, while 58% of the included studies reported that creep feeding in lactation improved piglet performance during the nursery phase. Creep feeding increased the average piglet body weight (creep = 7.23 ± 0.30, no creep = 6.96 ± 0.31; p = 0.03) and litter weight (creep = 81.2 ± 4.18, no creep = 76.4 ± 4.22; p < 0.001) at weaning. The average piglet body weight and litter weight were positively associated (p < 0.001 and p < 0.001, respectively) with total creep feed intake. Creep feeding of piglets for more than 14 days increased (p = 0.003) the litter weight at weaning compared to litters not provided or provided for shorter periods with creep feed. The present work strengthened the notion that creep feeding during lactation presents opportunities for improving weaning weights and post-weaning piglet performance compared to litters not provided or provided for shorter periods with creep feed.

The composition of mother’s milk is considered the ideal diet for neonates. This study investigated how conserved or variable the amino acid profile of sow colostrum and milk is throughout lactation, compared with other studies in sows and other species. Twenty-five sows (parity one to seven) from one farm with gestation lengths of 114 to 116 d were sampled on d 0, 3, and 10 after parturition. The total amino acid profile of the samples was analyzed through ion-exchange chromatography, and the results were displayed as the percentage of total amino acid and compared with literature data. Most of the amino acid concentrations in sow milk decreased significantly (p < 0.05) throughout the lactation period, while the amino acid profile generally showed a conserved pattern, especially from d 3 to d 10, and was rather similar across different studies. Glutamine + glutamate was the most abundant amino acid in milk at all sampling moments, accounting for 14–17% of total amino acids. The proportions of proline, valine, and glycine in sow milk nearly accounted for 11%, 7%, and 6% respectively, and were higher compared to human, cow, and goat milk, while the methionine proportion was less than the other three. Compared to the large variations often reported in macronutrient concentrations, the amino acid profile of sow milk in the present study, as well as in others, seems well conserved across the lactation period. Similarities with characteristic differences were also observed between sow milk and piglet body composition, which might reflect the nutrition requirements of preweaning piglets. This study warrants further research exploring the link between the whole amino acid profile and the particular amino acids for suckling piglets and could facilitate insight for optimizing creep feed.

Introduction: The effect of dietary fiber on pig production has been extensively evaluated. Inspired by observations of the diet of wild, young piglets, this study aimed to examine the possibility of feeding grass hay to suckling piglets besides concentrated creep feed.Methods: The sow-nursed piglets in this study were divided into two groups based on balanced sow parities. The control group (CON, n = 7 sows) only received a regular, concentrated creep feed, while the treatment piglets (GH, n = 8 sows) were also provided with chopped grass hay from 2 days of age until weaning (28 days). At weaning, one piglet with a median weight was selected from each litter for post-mortem evaluation. Subsequently, six pigs around median weight per sow were grouped into nursery pens and monitored for their feed intake and body weight gain until 9 weeks of age.Results and discussion: Piglets in GH consumed, on average, 57 g of grass hay per piglet during the entire lactation period. The emptied weight of the small and large intestine was significantly greater in GH (280 vs. 228 g, 88.8 vs. 79.3 g, respectively, p < 0.05), and the length of the large intestine was stimulated by the grass hay (164 vs. 150 cm, p < 0.05). Morphologically, the villus height in the jejunum was higher in GH (p < 0.05). In the large intestine, the crypt depth of the mid-colon was lower in GH. Moreover, the short-chain fatty acid (SCFA) concentrations in the cecum were increased in GH compared to CON (1,179 vs. 948 µmol/g dry matter, p < 0.05), whereas in the colon, SCFA concentrations were lower in CON (341 vs. 278 µmol/g dry matter, p < 0.05). There was no major impact of grass hay inclusion on the colonic microbiota composition. Only a trend was observed for a lower inverse of the classical Simpson (InvSimpon) index and a higher abundance of Lactobacillus genera in GH. After weaning, no significant differences in feed intake and body weight gain were observed. In conclusion, supplementing the grass hay to suckling piglets led to alterations in intestinal morphology, increased SCFA fermentation in proximal sections of large intestine, stimulation of gastrointestinal tract growth, and subtle modifications in colonic microbiota.

Background: Based on observations in feral pigs, the role of dietary fibre and structure may be underestimated in suckling piglet nutrition. This study investigated the effect of grass hay offered to suckling piglets either separately or included in their creep feed, combined with nursery diets with or without grass pellet inclusion on growth performance and gastrointestinal development. Methods: Thirty-six litters (14–15 piglets per litter) were divided into three equal groups of 12 litters per treatment during the suckling phase: control group (CON) received regular creep feed; GH group received chopped grass hay as-is in separate feeders alongside regular creep feed; PGH group received regular creep feed but barley and wheat were replaced by 28% grass pellets. After weaning (d 23), each litter was split into two dietary treatments in a split-plot design (pre-wean treatment as main plot). Two of the pre-wean diets were also offered until d 14 post-weaning, i.e., CON (CON nursery diet, CON-C, GH-C, PGH-C) and PGH (GH nursery diet, CON-GH, GH-GH, PGH-GH). Thereafter, transitioning to a diet containing 13% wheat/barley or grass pellets, respectively, until d 39 post-weaning. Gastrointestinal morphology, gene expression of intestinal nutrient transporters and barrier proteins, metabolite profile and microbiota were assessed on the day before weaning, d 10 and d 38 post-weaning. A total of 24 piglets were sacrificed at each dissection point. Results: At weaning, GH group had consumed 7 g/piglet grass hay, and PGH group had consumed 46 g/piglet creep feed. One day before weaning, GH piglets showed heavier emptied small intestine (P = 0.044) and colon (P = 0.065), higher SCFA production in proximal segments and lower SCFA production in colon (P < 0.05). Higher abundance of Prevotellaceae NK3b31 group was observed in caecal and colonic content of PGH compared to GH group (P < 0.05), and PGH group showed a lower energy conversion ratio (net energy intake/gain, P = 0.035). Following weaning, GH nursery group had a reduced average daily gain (226 vs. 183 g, P < 0.001) during d 0–14, while this group showed compensatory growth afterwards (P = 0.056). Main plot effects on increased expressions of CLDN3 and FFAR2 were observed in GH and PGH by d 38 post-weaning (P < 0.05). An interaction effect showed greater luminal abundance of the Prevotellaceae NK3b31 group in GH-GH and PGH-GH groups compared to CON-GH on d 38. The GH nursery diet showed a better energy conversion ratio (P = 0.006) with no influence on body weight and their SCFA production shifted towards proximal segments. Conclusion: In conclusion, feeding a structured and fibre-rich diet to suckling piglets enhance their digestive tract development and adapt their microbiome to fibre digestion in later life. Maintaining a fibre-rich diet from suckling to nursery is recommended, though this come with a transient reduction in weight gain caused by lower feed intake that, however, can be recovered afterwards accompanied with an optimized energy conversion ratio.

Background: The often disappointing intake of creep feed by suckling piglets coincides with a limited ability to cope with challenges such as weaning diarrhoea. Investigating the dietary nutrient profile of piglets (Sus scrofa) in the wild may help to improve nutrition for farmed piglets. This study was conducted to analyse the stomach content of feral piglets and their farmed counterparts, and to compare them with the composition of commercial creep feeds. Forty feral piglets (4.6 ± 1.4 kg) living in a wild herd were tracked and legally hunted in the Bahía Samborombón (Buenos Aires, Argentina). Their gastric contents were collected for analysing macronutrients. Twenty-eight farmed suckling piglets of similar ages were sourced from a Dutch research farm, and their stomach contents were collected and pooled into fourteen samples with the same procedure for comparison. Additionally, the composition data of twenty-five commercial feeds was also collected. Results: A higher dry matter content was observed in the farmed piglets’ stomachs (233 vs. 148 g/kg, P < 0.05). The gastric crude protein concentration was similar between both groups but the crude fat concentration was higher in the stomach of farmed animals (525 vs. 238 g/kg DM, P < 0.05), while feral piglets consumed more ash and fibre (P < 0.05). A similar concentration of non-fibrous carbohydrates (NFC) on metabolizable energy basis was observed by calculation through the NRC’s guideline (P > 0.05). Within the fibre content, significantly greater concentrations of neutral detergent fiber (NDF), acid detergent fiber (ADF) and acid detergent lignin (ADL) were observed in the stomach of feral piglets than in those of farmed piglets (282 vs. 36 g/kg, 158 vs. 9 g/kg DM, 53 vs. 3 g/kg DM, respectively, P < 0.05). Similar protein concentrations were observed between the gastric content of feral piglets and creep feed, while significantly higher crude ash and crude fat concentrations were found in feral piglets’ consumption (P < 0.05). Conclusion: In conclusion, piglets in natural conditions consume much more fibre—from coarse plant material—compared to farmed piglets receiving creep feed. Although technical performance is distinctly different between nature and farm, it raises the question whether suckling piglets under farming conditions would benefit from a more fibrous and coarser creep feed.