Nutritional requirements for pigs and an update of the Brazilian Tables 2024 (I): Energy and amino acids for growing pigs

Since 1983, the Brazilian Tables for Poultry and Swine: Feedstuff Composition and Nutritional Requirements have provided data on the main feedstuffs used in feeding, their main components, nutritional values, standardized ileal digestible amino acid values, and suggestions for ingredient inclusion levels. They update growth curves and nutritional requirements of animals according to category, stage of development, and production objective, considering that continuous genetic improvement interferes with weight gain rates, nutrient use efficiency, and distribution of proteins and body fats.

The objective of these articles, divided into two parts, will be to show in a simplified way the basis for updating the nutritional requirements of energy and amino acids for growing pigs in TBAS 2024 (Rostano et al. 2024) and the importance of using the presented models that can be applied to systems at different production levels.

Energy and nutrient requirements for growing pigs

For growing pigs, the basis of TBAS 2024 (Hannas et al 2024) starts with determining growth curves for castrated males, females from birth to finishing, entire males from birth to 100 kg live weight, and immunocastrated males from 100 to 140 kg live weight, as well as establishing energy requirements, digestible lysine, amino acid composition in ideal proteins, essential fatty acids, macrominerals, microminerals, and vitamins.

The main energy and digestible lysine requirements were determined using factorial models that consider their maintenance and production requirements, thus incorporating experimental dose-response trials.

Metabolizable energy requirements

Determining the energy requirement for maintenance ensures that, when met, the animal is in an energy balance of zero, meaning it is in a condition where there is no increase or decrease in body energy. It is established based on the average metabolic body weight of the animal in that phase.

Energy requirements for production were established based on the animal's average body weight and the animal's rate of weight gain in the production phase. In this scenario, equations were established for castrated males, females, entire males, and immunocastrated males.

For entire and subsequently immunocastrated males, different equations for predicting energy requirements must be applied since when these animals receive the second dose of the immunocastration vaccine, there is a change in consumption behavior and nutritional requirements, which implies a change in the response of these differentiated animals.

For the equations to be applicable in day-to-day production systems, the equations used to estimate metabolizable energy requirements (Table 1) only require live weight information at the initial and final ages of the phase to determine the average live weight and rate of weight gain of the animals expected for the phase. These data can be obtained directly from the genetics used in production or from data from the production systems themselves.

Table 1. Metabolizable energy requirement in kcal/day for growing pigs

¹Considering the average pig performance is 3% less efficient, W: Average weight, G: Average weight gain.

As explained by the authors, for male castrated pigs and female pigs with average performance,the equation to estimate the daily metabolizable energy requirement was adjusted 3% higher due to the increased production, management, environmental, and health challenges in these production systems.

The target feed intake for pigs can be estimated by considering the relationship between their metabolizable energy (ME) requirement in kcal/day and the ME level in the diet. To do this, the nutritionist must formulate the diet within certain ME limits, taking into account the composition of the ingredients to avoid negative impacts on intake. In addition, it is essential to consider the feed conversion target when setting these parameters.

Tables 2, 3, and 4 provide a summary of the ME requirements, dietary ME value, and expected feed intake for sows, castrated males, and entire and immunocastrated high-performance pigs. It should be mentioned that when using different concentrations of diets, the expected feed intake will change, requiring adjustments in the concentration of other nutrients.

Using the equations and parameters of live weight and weight gain, it is possible to estimate the energy requirements of animals in different conditions, thus making it possible to customize feeding programs according to the reality of production and its characteristics.

Table 2. ME requirements and feed consumption of sows with high genetic potential and superior performance.

¹Diets containing 3350 kcal/kg ME from 49 to 182 days of age. Adapted (Hannas et al. 2024)

Table 3. ME requirements and feed intake of castrated male pigs with high genetic potential and superior performance.

¹Diets containing 3350 kcal/kg ME from 49 to 182 days of age. Adapted (Hannas et al. 2024)

Table 4. ME and feed intake requirements of entire and immunocastrated male pigs with high genetic potential and superior performance.

¹Diets containing 3250 kcal/kg ME from 49 to 182 days of age. Adapted (Hannas et al.2024)