# Poor Maternal Diet During Gestation Alters Offspring Muscle Morphometrics, Collagen Gene Expression, and Meat Tenderness in Sheep

## TL;DR

A poor maternal diet during pregnancy affects the muscle and meat quality of sheep offspring, changing fiber size and tenderness.

## Contribution

This study reveals how maternal diet during gestation alters muscle characteristics and gene expression in sheep offspring, impacting meat quality.

## Key findings

- Offspring from restricted-fed ewes had larger longissimus muscle fibers but smaller semitendinosus fibers.
- Offspring from overfed ewes had more tender loin chops compared to control or restricted-fed groups.
- Maternal diet altered gene expression related to muscle and collagen formation in offspring muscles.

## Abstract

Poor maternal nutrition during gestation alters the muscle growth of offspring, but how that impacts meat characteristics and quality is not well defined. Male offspring of ewes fed a restricted-fed diet had a greater longissimus muscle fiber size but reduced semitendinosus muscle fiber size, with no differences in longissimus or semitendinosus muscle weight. Offspring of ewes fed an overfed diet had loin chops that were more tender than offspring of restricted- or control-fed ewes. There were no differences in back fat or longissimus muscle collagen content as a result of maternal diet. However, gene expression related to muscle and collagen formation, and epigenetic markers, were altered as a result of maternal diet. These results suggest that a poor maternal diet impacts the meat characteristics that may alter the meat quality of sheep.

We hypothesized that maternal overfeeding and restricted feeding during gestation would alter the collagen content, muscle fiber cross-sectional area (CSA), and meat tenderness in offspring. Pregnant ewes were fed 100% (CON), 60% (RES), or 140% (OVER) of their requirements from day 30 of gestation until parturition. Male offspring were necropsied at 282 ± 1.8 days of age. Gene expression and CSA were quantified in the longissimus (LM) and semitendinosus (STN) muscles. The Warner–Bratzler shear force (WBSF) was quantified in LM. Data were analyzed by one-way ANOVA, with diet as a fixed effect. Differences were considered significant at p ≤ 0.05 or a tendency at p ≤ 0.10. Semitendinosus CSA was smaller in OVER and RES than CON rams (p = 0.02). Longissimus CSA was larger in RES than OVER and CON rams (p = 0.002). OVER LM had reduced WBSF compared with CON rams (p = 0.03). Myogenic genes bone morphogenic protein 1 (BMP1) and paired box 7 were greater in RES LM than OVER (p ≤ 0.02). Maternal diet altered the fibrogenic genes fibronectin 1 (p = 0.07), lysyl oxidase (p = 0.07), and collagen 1A1 (COL1A1; p = 0.08) in the LM and COL1A1, COL3A1, and BMP1 (p ≤ 0.09) in the STN. Poor maternal diet during gestation alters muscle and meat characteristics that may impact meat quality.