# Is the Mineral Content of Muscle Tissue (Longissimus Lumborum) in Cattle Finished During the Rainy Season in the Eastern Amazon Influenced by Different Farming Systems?

## TL;DR

This study examines how different farming systems in the Eastern Amazon affect the mineral content of beef muscle tissue during the rainy season.

## Contribution

The study provides new insights into how farming systems in the Amazon influence the mineral composition of beef.

## Key findings

- Amazonian farming systems influence macro and micromineral content in cattle muscle tissue.
- Extensive pasture vs. feedlot systems show differences in minerals like calcium, magnesium, and phosphorus.
- Cultivated pasture systems differ from extensive pasture in all evaluated minerals.

## Abstract

The scientific literature currently lacks studies that evaluate the nutritional composition of the tissues of cattle raised in different systems, so that the nutritional effects can be known and used to maximize consumption and use in human diet. The aim was therefore to assess whether the mineral content of muscle tissue (longissimus lumborum) in cattle finished during the rainy season in the Eastern Amazon is influenced by different farming systems: 1. Native wetland pasture in Santa Cruz do Arari (Marajó Mesoregion); 2. Native wetland pasture in Monte Alegre (Lower Amazon Mesoregion); 3. Cultivated dryland pasture in São Miguel do Guamá (Northeast Pará Mesoregion); and 4. Confinement, in Santa Izabel do Pará (Mesoregion of Metropolitan Belém). The Amazonian systems influenced the macro and micromineral content in the muscle tissue of the cattle. The interaction between extensive pasture vs. extensive feedlot systems showed differences in the minerals calcium (Ca), magnesium (Mg), phosphorus (P), copper (Cu), zinc (Zn), iron (Fe) and manganese (Mn). In this way, the farming systems in the Eastern Amazon influence the mineral content of beef, which remains an excellent source of macro- and microminerals and can be part of the human diet.

The scientific literature currently lacks studies that evaluate the nutritional composition of the tissues of cattle raised in different systems, so that the nutritional effects can be known and used to enhance consumption and use in the diet. The aim was therefore to assess whether the mineral content of muscle tissue (longissimus lumborum) in cattle finished during the rainy season in the Eastern Amazon is influenced by different farming systems. The treatments consisted of four systems (three pasture production systems and one feedlot system). 1. native wetland pasture in Santa Cruz do Arari (Mesoregion of Marajó); 2. native wetland pasture in Monte Alegre (Mesoregion of Baixo Amazonas); 3. cultivated dryland pasture in São Miguel do Guamá (Mesoregion of Nordeste Paraense); and 4. Confinement in Santa Izabel do Pará (Metropolitan Region of Belém). The analyses were carried out on samples of the longissimus lumborum muscle tissue of 48 male, castrated, crossbred Nelore cattle, twelve per breeding system, from commercial farms, destined for meat production, finished during the rainiest period of the year (between January and June). In systems 1 and 2, the animals were slaughtered in licensed slaughterhouses; the animals in systems 3 and 4 were slaughtered in commercial slaughterhouses. Food sampling and chemical analysis, soil sample collection and analysis, longissimus lumborum muscle tissue collection, sample preparation and digestion, and inductively coupled plasma optical emission spectrometry were evaluated. The experimental design was completely randomized in a linear model with four rearing systems and one period (rainy). The data was compared using the Statistical Analysis Systems (SAS) program. All analyses were carried out considering a significance level of 0.05. Samples of the diets offered (pasture and concentrate) were also collected. The Amazon systems influenced the macro- and micromineral content in the muscles of cattle (p < 0.05). The interaction between pasture systems vs. confinement showed differences in the minerals calcium (Ca), magnesium (Mg), phosphorus (P), copper (Cu), zinc (Zn), iron (Fe), and manganese (Mn) (p < 0.05). However, there was no difference in the values of sodium (Na), potassium (K), and sulfur (S) between the rearing systems (p > 0.05). By contrast, the cultivated pasture system vs. extensive pasture showed differences in all the elements evaluated (p < 0.05). The rearing systems of the Eastern Amazon influenced the mineral content of beef, which continues to be an excellent source of macro- and microminerals and can compose the human diet.