Low-protein diets while meeting amino acid requirements

Low-protein diets while meeting amino acid requirements

Field trial data shows that amino acid needs can be met through a low-protein diet that reduces the risk of GI.

October 5 2022

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There are many factors affecting pig production these days. Rising feed costs, antibiotic growth stimulators banned in some countries, and ZnO banned as a medical treatment in others. Diseases have infected many countries around the world challenging the production environment as we know it.

Some of these challenges have allowed strategies to feed weaned pigs with low-protein diets. This is due to the well-known fact that low protein diets can reduce the risk of diarrhea/diarrhea in piglets.

Feeding piglets less crude protein has several effects on their gut health. Given that many gut health problems arise from bacterial growth in the distal ileum and in the colon, restricting the supply of N to these bacteria will keep their growth in check.

The reasons for this are:

  1. The protein components have a higher acid storage capacity than the grains. By reducing the protein content, it becomes easier to maintain a lower pH in the stomach. This improves the effectiveness of the gastric enzyme pepsin, the first protein-degrading enzyme in the digestive system.
  2. Less protein in the feed means that the undigested protein goes into the colon. When less protein enters the GI tract with feed, it is also normal for less indigestible protein to enter the colon from the ileum. This is of course given that the average quality protein has the same digestibility.
  3. Protein components are usually the main carriers of anti-nutritional factors (ANF’s). As the crude protein content increases, the chance of increased trypsin inhibitor activity also increases. Since trypsin inhibitors inhibit proteases in the gut, less protein is digested. More protein will travel to the colon, where it can increase the growth of harmful bacteria and diarrhea. Beta-conglycinin from soybean meal (SBM) will destroy the epithelium of the small intestine of piglets and reduce amino acid absorption, leaving more nitrogen for the bacteria as well. The lower protein content also reduces the concentration of beta-conglycinin coming from the SBM.

However, with a crude protein content as low as necessary to significantly reduce the risk of diarrhea, it is no longer possible to cover the required amino acid profile for all essential amino acids. Specifically, Isoleucine and Histidine will end up well below the requirement in the concept of ideal amino acids.

As these amino acids then become the limiting amino acids for growth and other expressions of life, other amino acids are not used to build proteins but instead as an energy source (ideal amino concept).

This means delayed animal growth and increased feed conversion rates. Excess nitrogen from the breakdown of excess amino acids will be excreted through urine with the energy cost of the animal in addition to the loss of valuable amino acids.

Nutrition concept

In Hamlet Protein we propose another way to feed weaning pigs under these new restrictions.

Regardless of anything that can be done in and managed in the pig’s environment, the approach using a more digestible protein source in the diet with Bio-Functional Fiber (HP 300 + HP FiberBoost) has proven to be very successful.

using HP 300 As a major source of protein, amino acid requirements can be met, at least to a higher degree, within the specified crude protein limit to ensure a low risk of diarrhea. HP 300 It has a high affinity for standard ileal digestibility, and this reduces the amount of undigested protein that goes into the large intestine. At the same time HP 300 It has a very low ANF content and does not irritate the intestinal surface or damage gut proteases.

Buffer capacity of HP 300 Less per unit of protein than some other SBM products and the final buffer capacity of the diet can be easily regulated by adding organic acids to the final compound diet.

Prebiotic fiber from HP FiberBoost Supports the growth of beneficial bacteria that produce short-chain fatty acids in the gut such as butyric acid as evidenced by various experiments where HP FiberBoost It was added to the feed.

Feed trials supporting this feeding concept demonstrate equal performance and gut health standards for pigs fed high doses of ZnO as a medicinal additive.

Table 1 Performance of pigs fed one of four feedings (LPC: 17% CP, no added fiber; LPF: 17% CP, HP FiberBoost; HPC: 19% CP, no added fiber; HPF: 19% CP, HP FiberBoost) 0 – 41 days after weaning.


nutritional therapy


q value





N, pens





black and white d0







BW d41







ADG, kg / d







ADFI, kg / d







FCR, kg/kg







death rate ,%





0.13 *

Standardization, CoV,%






0.23 *



Note: ADG = Average Daily Profit; ADFI = average daily intake of forage; FCR = feed conversion ratio; Uniformity was calculated as the coefficient of variation (CoV; mean/SD*100). High letters a, b, and c show significant differences (P < 0.05) between the experimental groups.

* Mortality: The main effect of adding HP FiberBoost is a quasi-significant trend (p = 0.06); Standardization: For the main effect of adding HP FiberBoost, p = 0.15.

Based on component prices as of April 2022.

In the above experiment, LPC was the control diet with low protein (17%) and no added fiber. LPF is low in protein with added fiber. HPC was high in protein (19% = natural) and had no added fibre, and HPF had high protein and added fibre.

As can be seen, ADG was improved by 40+ grams by maintaining normal protein level in diets with HP 300 (Table 1).

The FCR worsened by 0.08 kg/kg when the protein was reduced from 19 to 17%. The role of fiber is to build security to support overall health and resilience, as evidenced by the tendency to lower mortality, exemplified by reduced cuts/diarrhea. Interestingly, the addition of fiber improves the homogeneity of the pigs, which is a high value for the product.

The concept of protein nutrition combines in Hamlet HP 300 And the HP FiberBoost It can help maintain or restore performance in situations where antibiotics and/or high doses of ZnO are not permitted. Using the concept of Hamlet protein feeding, it is possible to maintain the correct physiological supply of amino acids to weaned pigs, ensuring good performance and health as well as low nitrogen excretion into the environment and a good production economy.

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