Increasing fat deposition and feed conversion ratio over the days in finishing phase directly influence pork quality and productive profitability. Nonetheless, the slaughter of heavier pigs can result in benefits for the slaughterhouse due to dilution of production and processing costs, as well as economic benefits for the pig producer resulting from the dilution of production costs. Therefore, dietary supplementation of chromium for finishing pigs of high lean-genotypes is a strategy to increase lean tissue accretion and minimize fat deposition, reflecting positively on growth performance. This review discussed recent studies results and mechanisms of action of this modifier of performance and carcass a traits in finishing pigs. Chromium increases the insulin action, facilitating insulin binding to the receptors on cell membrane. As a result, insulin-sensitive cells uptake more glucose, which will be later converted into energy. This additional energy is use to increase protein synthesis, thereby increasing the amount of lean tissue and reducing fat content in the carcass, without altering protein intake by pigs. Chromium also reduces lipid oxidation rate maintaining meat quality for longer period. In conclusion, dietary Cr supplementation for finishing pigs have shown that 0.2 mg/kg of organic Cr sources for pigs from ~60 kg until the slaughter can improve growth performance, lean gain and reduce fat content in carcass. However, the development of nanotechnology has allowed the use of inorganic Cr source at 0.2 mg/kg of inclusion, leading to improve the growth performance and carcass traits of finishing pigs.

We evaluated the effects of L-arginine supplementation during the last third of gestation on molecular mechanisms related to skeletal muscle development of piglets and litter traits at birth. Twenty-three nulliparous sows averaging 205.37 ± 11.50 kg of body weight were randomly assigned to the following experimental treatments: control (CON), where pregnant sows were fed diets to meet their nutritional requirements; arginine (ARG), where sows where fed CON + 1.0% L-arginine. Skeletal muscle from piglets born from sows from ARG group had greater mRNA expression of MYOD (p = 0.043) and MYOG (p ≤ 0.01), and tended to present greater mRNA expression (p = 0.06) of IGF-2 gene compared to those born from CON sows. However, there were no differences (p > 0.05) in the histomorphometric variables of fetuses’ skeletal muscle. The total weight of born piglets, total weight of born alive piglets, piglet weight at birth, coefficient of variation of birth weight, and the incidence of intrauterine growth restriction (IUGR) piglets did not differ between groups. No stillborn piglets (p < 0.01) were verified in the ARG sows compared to CON group. The blood levels of estradiol (p = 0.035) and urea (p = 0.03) were higher in ARG sows compared to those from the CON group. In summary, our data show that arginine supplementation of nulliparous sows at late gestation enhance mRNA expression of key myogenic regulatory factors, which likely contribute to improve animal growth rates in later stages of development.

Objective: This study evaluated the effects of reducing crude protein (CP) and supplementing arginine plus glutamine–glutamate (AGG) on growth performance, diarrhea incidence, blood metabolites, amino acid profiles, nutrient digestibility, and nitrogen (N) utilization in nursery pigs.Methods: A total of 200 entire male and female piglets weaned at 20 d of age (4.8±0.58 kg) were allotted to 5 diets in a randomized block design: 22.5%, 21.0%, 19.5%, or 18.0% CP, and 18.0% CP supplemented with 5 g/kg L-arginine and 10 g/kg L-glutamine+glutamate. Pigs were fed in two phases (20–32 and 32–44 d of age) over a 24-d period.Results: Reducing dietary CP linearly decreased feed efficiency, with the lowest performance observed in pigs fed the 18.0% CP diet with AGG. Serum urea N and gamma-glutamyl transferase increased linearly with dietary CP level. Plasma arginine and ornithine were elevated by supplementation. Methionine, threonine, and valine were highest in pigs fed the 18.0% CP diets. In contrast, phenylalanine and tyrosine declined with reduced CP. Diarrhea incidence and fecal scores were greater in pigs fed the 22.5% CP, with each 1% CP increase raising diarrhea incidence by 3.55% points. Digestibility of protein and energy improved with increasing dietary CP, and pigs fed 22.5% CP showed the greatest N absorption but also higher fecal N excretion.Conclusion: Collectively, results indicate that reducing dietary CP from 22.5% to 18.0% compromises growth and nutrient digestibility, even when supplemented with arginine and glutamine–glutamate, but lowers diarrhea incidence and N output. These findings highlight trade-offs between growth efficiency, gut health, and environmental sustainability in nursery pig nutrition.