Optimising digestive capacity post-weaning

The nursery phase is the cornerstone of a thriving lifetime of growth performance. Therefore, it is crucial to boost the piglet’s ability to digest nutrients and set-up a healthy and strong status for lifetime growth and profitability. Dietary protease supplementation can do just that. These enzymes can optimise protein digestibility and help young piglets to thrive and carry on this benefit through later stages of life.

At weaning, there is a sharp decrease in the secretion of endogenous proteases (trypsin, chymotrypsin). In a study by Lindemann (1986), weaning piglets had a drastic and sharp decrease in endogenous protease secretion during weaning which took more than two weeks to recover to normal secretion levels. This decline in endogenous protease secretion causes an increased flow of undigested protein to the hindgut. The excess protein is fermented by micro-organisms there, generating ammonia which is detrimental to gut health and digestive capacity.

Dietary protease supplementation can compensate for the decrease in secretion of endogenous protease and increase digestive capacity of nursery piglets. An experiment tested protease supplementation with 190 nursery piglets fed diets with or without protease added. Ammonia nitrogen in the digesta was measured as an indicator of undigested protein in the gut. Nursery piglets fed diets supplemented with protease had less undigested protein in the hindgut as indicated by less (P < 0.05) ammonia nitrogen concentration in the digesta at various locations along the intestinal tract (Figure 1).

Consequently, piglets grew stronger with better gut health and better digestive capacity.

As piglets supplemented with protease have less undigested protein reaching the hindgut, there is less bacterial fermentation in the gut and intestinal lining cells are better preserved. In the same trial, piglets fed diets supplemented with protease had higher (P = 0.08) ileum villi and had lower (P < 0.01) crypt depth (Figure 2) when compared to piglets fed non-supplemented diets. Altogether, higher villi and lower crypt depth means more surface area for nutrient absorption and more digestive capacity for optimum growth.

Figure 2 – Protease supplementation optimises Ileum villus height and alleviate crypt depth in Ileum of nursery piglets.

Impact of weaning on gut health

After weaning, especially during the first week, piglets have very low feed intake and growth rates. The malnutrition or even starvation at weaning severely hurts the intestinal lining cell morphology of piglets. Villi become much shorter and crypts much deeper which limit the gut surface area for proper digestion and absorption of dietary nutrients, compromising gut barrier function against pathogens. Consequently, piglets experience poor feed conversion and diarrhoea, leading to high economic losses. However, improving feed intake right after weaning can ameliorate these gut health challenges and support better digestion.

Experiments have shown that protease supplementation helps to improve feed intake so piglets can get back to better growth rates faster after weaning. This is due to the gut lining morphology being preserved and digestive capacity being optimised. An experiment was conducted with 1,200 nursery piglets fed diets without or with protease supplementation for 24 days post-weaning. Piglets fed diets supplemented with protease had an increase (P < 0.03) in feed intake compared with piglets fed non-supplemented diet. The greater difference in feed intake observed was a 20% increase (P < 0.03) during the first week post-weaning. This first week is the most crucial period of the transition of diet and environment. During the second and third weeks after weaning, feed intake was increased by 5% (P < 0.02).

Overestimating amino acid digestibility

Besides undigested protein in the hindgut and poor feed intake after weaning, other factors can critically diminish digestion and absorption capacity in nursery piglets. Overestimating amino acid digestibility values is among these issues. Most digestibility values for amino acid and crude protein used in nursery diets formulation are obtained from trials using growing or finishing pigs. The reality for piglets is poor amino acid digestion and increased undigested protein in the hindgut, which poses a critical gut health and performance issue. Therefore, nursery piglets are being fed less amino acids than what really is required which is aggravated by their low endogenous protease secretion and digestion ability. Therefore, increasing protein supplementation may not only increase growth rate, but also increase the flow of undigested protein to the hindgut (causing increased diarrhoea incidence and severity).

Protease supplementation can compensate for the decreased secretion of endogenous protease at weaning and can help pigs digest more protein than they otherwise would. As a result, digestive capacity and nutrient absorption are increased, resulting in better growth performance. An experiment with 990 nursery piglets tested the effect of protease supplementation on nursery diets. When analysing average daily gain, a 7.7% increase was recorded where the control had a 0.36 kg/day and those fed protease had 0.39 kg/day. Feed efficiency of protease supplemented piglets was also improved by 2.3% compared with piglets fed non-supplemented diets. Piglets that were supplemented with protease were 1kg heavier when exiting the nursery and had better feed conversion, which indicates better nutrient digestibility.

In summary, protease supplementation (Cibenza DP100 feed enzyme, Novus International) to nursery diets alleviates many challenges faced during this phase. Dietary protease compensates for the reduced secretion of endogenous protease at weaning, thus increasing digestion of nutrients. Also, protease supplementation increases feed intake of nursery piglets and helps maintain intestinal cell lining morphology, thus increasing nutrient digestion and absorption capacity of piglets. Moreover, the overestimated amino acid digestibility values of piglets that may result in the reduction of piglet performance can be alleviated by protease supplementation.