Piglet morbidity and mortality are a major welfare concern and source of economic losses, with gastro-intestinal problems ranking amongst the highest causes. With the further restrictions of antimicrobials, pig production will continue to face challenges. But with an integrative approach combining pre- and post-weaning nutritional strategies, the risk of gastro-intestinal problems can be reduced.
Researcher Swine Nutrition
Schothorst Feed Research (SFR)
Researcher Swine Nutrition
Schothorst Feed Research (SFR)
Weaning is one of the most stressful events the pig has to encounter throughout their life. Piglets at 3-4 weeks of age still mostly depend on sow milk, whilst at weaning they are ought to eat solid feed. This change in diet (in composition and presentation) is one of the major challenges at weaning and will result in (short term) decreased feed intake and damage of the gastrointestinal tract (GIT). This will cause villous atrophy and compromise piglet immune function, resulting in ineffective nutrient utilisation, intestinal inflammation, and gut microbiota dysbiosis. The latter, will put the piglet at risk for reduced growth and post-weaning diarrhoea. It is therefore no surprise that most antimicrobials are used in the nursery barn.
THE GUT AS GATEKEEPER OF HEALTH
Gut health is established during early life (both in utero as well as the first 3 months of life) and supporting piglets gut health seems more relevant than ever:
• The increase in prolificacy and selection for leaner meat has led to more piglets born, but also less viable piglets such as low birth weight piglets and intra-uterine growth retarded piglets, as well as piglets with limited body reserves.
• The production of colostrum, ‘the elixir of life’, is independent of litter size, meaning an increase in litter size results in less colostrum per piglet. Colostrum is not only important for immune functioning and as an energy source, but also plays as important role in the development of the GIT.
• The further restrictions of copper, zinc, and in-feed antibiotics in post-weaning piglet diets that previously were able to mask gastrointestinal infections making the problem even more problematic.
• Also with respect to food safety it is important to reduce the prevalence of GIT illnesses in piglets. E. coli is one of the most important GIT problems in piglets, and a high degree of antibiotic resistance of pathogenic E. coli has been found to tetracyclines, streptomycin and ampicillin, posing a serious problem for animal welfare and public health.
These challenges that pig producers encounter require an integrative nutritional approach that combines interventions during the pre- and post-weaning period. Various studies have shown that early life programming of the GIT already during the suckling period can have long-term effects. One of those is that piglets pre-weaning microbial composition can predispose piglets to post-weaning diarrhoea as shown by French and Czech Republic studies (Dou et al, 2017; Karasova et al., 2021). In the following paragraphs we will summarize some of the early nutritional interventions that can be utilised to shape piglets’ gut for successful weaning.
START WITH THE SOW TO SUPPORT PIGLET GUT DEVELOPMENT
The diet of the sow around farrowing plays an important role in piglet gut health. Piglets are born relatively sterile, in which particularly the microbiota in the sow’s colostrum, milk, and faeces drives the development of the piglet microbiota. Additionally, the sow’s diet is key for the quantity and quality of colostrum, as well as for the intestinal barrier function of their piglets, for example via prebiotic features of dietary fibre. The sows’ diet can thus modulate gut maturation of her offspring via different routes. A recent study at SFR showed that additional inert fibre given to sows around farrowing modulated the gut microbiota of their piglets at least up to three weeks after the sow dietary treatment ended. The supplementation with inert fibre via the sows’ diet supported a diverse microbial community in the piglet’s gut, which is associated to be more efficient and resilient for pathogenic bacteria. For example, a lower abundance of the potential pathogen Clostridium was observed. In addition, the addition of extra fibre in sow diets have shown in other studies to reduce piglet diarrhoea and associated antibiotic treatments. The gut-modulatory effects as result of the sow diet may be prolonged if such nutritional strategies are continued in piglets their own feed.
PIGLET NUTRITION WITH A DUAL PURPOSE
Supplemental milk: can we learn from infant formulas to improve gut health?
The number of (productive) teats per sow does not match the increase in prolificacy. This result in that not all sows can rear the piglets on their own and additional management and nutritional interventions may be necessary to improve piglet performance and survival. Milk cups are commercially available and can provide fresh milk throughout the day. These systems may be especially (economically) relevant for pig producers that make little or no use of nurse sows or pig producers that apply minimal or no cross-fostering. The intake of supplementary milk is variable between litters and within litter and mostly depends on the milk production of the sow. In addition, supplemental milk does not have the same nutritional quality as sow milk. While supplemental milk can be provided with the aim to supplement sow milk, it may also be utilised in a way to stimulate GIT development, thus having a functional role next to a nutritional role. A study from Wageningen University has shown that supplemental milk had the ability to influence gut morphology of sow reared piglets (de Greeff et al., 2016) and enhanced small intestinal growth, cell proliferation, and increased the production of short-chain fatty acids (important energy sources for intestinal cells) in the large intestine. A Chinese study furthermore showed that feeding supplemental milk to suckling piglets could modulate the microbiota colonisation in the GIT and reduced the relative abundance of E. coli, which may reduce the incidence of diarrhoea (Shi et al., 2018). Most other studies evaluating the effect of functional ingredients (e.g. prebiotics, wheat) on piglet gut health and development used the piglet as a model for human infants and reared the piglets artificially. For instance, a study from Copenhagen suggested that gradually fortifying supplemental milk with wheat was able to increase the production of carbohydrases, indicating that the GIT was adapting towards a plant-based diet. Nonetheless, the intakes of such milk replacers will be higher in artificial- than sow-reared piglets and thus warrants further investigation.
Creep feeding: preparing piglets for weaning
While both supplemental milk as well as creep feed can serve as early life gut modulators, there are also notable differences why to use one or the other in relation to piglet performance (Figure 1). Supplemental milk is aimed at supplementing sows’ milk and therefore to improve pre-weaning performance. However, creep feed is aimed to prepare the piglets for weaning and therefore to improve post-weaning performance and often has only marginal effects on pre-weaning production. Piglets have the ability to suckle and drink from birth, however to eat solid feed they need to develop their teeth, oral motor skills, and mastication muscles. Creep feed thereby prepares piglets behaviourally, by getting piglets familiar with solid feed. On the other hand, creep feed also prepares piglets physiologically, by learning them how to digest and ferment the feed ingredients that are not in sows’ milk and that they will encounter post-weaning.
One of the physical challenges that piglets have to encounter during the post-weaning period is their inability to acidify their stomach sufficiently for the onset of protein digestion and to function as an antimicrobial barrier. During the suckling period, the fermentation of lactose in sows’ milk acidifies the stomach to a pH of 4, but inhibits the production of HCl at the same time. This inhibitory effect of HCl only disappears when solid feed becomes a main source of the diet, but this takes time. However, an UK study suggested that with the provision of creep feed (formulated without acidifiers) an acid-secretory response can be initiated already during the pre-weaning period (Lee et al., 2021). This suggests that feeding piglets creep feed will better prepare the piglet for gastric digestion of complex plant proteins during the immediate post-weaning period.
Creep feed benefits for post-weaning performance: due to feed intake or diet composition?
Creep feed is known to stimulate gut and gut microbiota development of piglets, supplement sow milk production if necessary, reduce post-weaning fasting and improve post-weaning performance (i.e. feed intake and body weight gain), but also may improve feed efficiency and reduce post-weaning diarrhoea. It is widely known that these positive effects are particularly occurring when high creep feed intakes are achieved. Formulating creep feed to be highly palatable and digestible has therefore received a lot of attention. This can, however, result in large differences between the creep feed and post-weaning diet in terms of composition. As a result, piglets may not adjust well to the grain-based post-weaning diet, even despite high creep-feed intakes are achieved. This has been demonstrated by, for instance, Korean research from 2018 that provided suckling piglets with either a conventional creep feed, a weaner diet or sow (lactation) diet before weaning and followed piglet performance after weaning, when all piglets were fed the same weaner diet. Litters that were fed with creep feed during the pre-weaning phase had a higher total feed intake pre-weaning as well as improved pre-weaning growth. Nevertheless, it were the piglets that received the weaner diet in both the pre- as well as post-weaning phase that had a higher post-weaning feed intake and growth than the other two groups. Piglets fed with a weaner diet or sow diet during lactation also tended to have longer villi at day 4 post-weaning compared to piglets fed creep feed during lactation. Taken together, the success of providing solid feed during the pre-weaning period stands or falls with the similarity of the diet pre- and post-weaning rather than (only) absolute creep feed intake and/ or diet composition. The main focus of creep feed formulation should therefore be to prepare the gut for weaning by using a low complexity diet (e.g. increase starch and non-starch polysaccharides content) and to stimulate intake of that particular diet.
A perfect match: a transition diet around weaning
The use of a transition diet around weaning is a good strategy to achieve a perfect match between the pre- and post-weaning diet (Figure 2). To provide GIT with sufficient time to adapt in terms of structure and function to the transition diet, it is recommended to start feeding this diet about one week before weaning. After weaning, the transition diet should not be replaced too soon. In the first days after weaning, also called ‘the acute phase’, the feed intake of the piglets is recovering and the gut is in dysbiosis as result of the large dietary change, in combination with the other stressors at weaning. It is therefore recommended to continue the transition diet up to one week after weaning.
CONCLUSION
With the challenges pig producers are facing it is therefore crucial to adopt an integrative approach (Figure 3), starting with nutritional strategies targeting the sow around farrowing to early life nutritional strategies for piglets, in order to reduce GIT problems in piglets. In the first days of life, the goal of dietary modulation is to increase the survival of piglets. In the weeks following birth, early‐life nutritional programming should focus on stimulating gut development and maturation. In addition to providing nutrients to piglets, supplemental milk and creep feed serve as a gut modulator in early life by incorporating functional ingredients, and thus serve a dual purpose. As weaning approaches, the focus should shift to preparing piglets for weaning by ‘matching’ the pre- and post-weaning diet (use of a transition diet), as well as achieving a high and stable feed intake. If you would like to learn more about SFR and our activities (independent research, nutritional advice and courses and training) visit our website or contact us.
About Dr. Anne Huting
Dr. Anne Huting did her PhD at Newcastle University, UK where she has been studying the effect of management (cross fostering, weaning age, creep feed) and post-weaning diets on piglets that were born and/ or weaned light. In addition, she identified which morphological characteristics at birth can distinguish piglets that are able to catch-up growth in later life. While finishing her PhD she started working as Researcher Swine Nutrition at the R&D department of SFR. She mainly focusses on feedstuff evaluation and the role of feeding concepts/ additives on weaned piglet performance.About Dr. Anouschka Middelkoop
Dr. Anouschka Middelkoop is an animal scientist graduate from Wageningen University. During her PhD, she has been studying creep feeding and the weaning transition in piglets in relation to pig behaviour, physiology and gut microbiota. Since she obtained her PhD she is working as Researcher Swine Nutrition with a focus on intestinal health at the R&D department at SFR.
