Leptin Gene Polymorphism in Goats Fed with Diet at Different Energy Level: Effects on Feed Intake, Milk Traits, Milk Fatty Acids Composition, and Metabolic State.

Marcella Avondo,Salvatore Bordonaro,Daniela Giorgio,Bernardo Valenti,Paola Di Gregorio,Anna De Angelis,Adriana Di Trana,Andrea Criscione

doi:10.3390/ani9070424

Abstract

Simple SummaryIn this study it has been highlighted the role of a leptin polymorphism on goat milk yield and quality and of its interaction with the energy content of the diet. Energy did not interfere with genotype effect. The studied leptin polymorphism increased healthy fatty acids in milk, thus representing a potential tool to improve functional characteristics of goat milk.The study investigated the effects of a polymorphism at the LEP gene intron 1 microsatellite region and its interaction with diet energy level on feed intake, milk traits, milk fatty acid composition, and metabolic state in goats. Sixteen Girgentana lactating goats at mid-lactation, selected on the basis of their genotype (8 goats homozygous 266 bp/266 bp, L genotype; 8 goats heterozygous 266 bp/264 bp, H genotype), were fed ad libitum according to a change-over design, with two diets at different energy levels reached with different hay inclusion: low energy diet (LE)—100% of hay; and high energy diet (HE)—65% of hay. No differences in milk yield and composition or in dry matter intake were found between leptin genotypes or between diets. Leptin genotype had no effect on plasma metabolite concentrations. The differences between diets were recorded for plasma β-hydroxybutyric acid (BHBA) concentrations with higher (p = 0.01) values for the HE compared to the LE diet (0.44 vs. 0.24 mmol/L, respectively). Nonesterified fatty acid (NEFA) values seem to indicate a positive energy balance in goats. No interaction genotype per diet was evident for most of the studied parameters. Fatty acid composition was strongly influenced by LEP genotype: L goats, compared to H goats, showed higher levels of monounsaturated fatty acids (MUFA), polyunsaturated fatty acids (PUFA), and 14:1/14:0 desaturation index; lower levels of saturated fatty acids (SFA); and a more favorable atherogenic index. These results seem to suggest an improvement of health characteristics of milk with the L genotype.

Highlights

Leptin is a protein hormone secreted from white adipose tissue
Studies with association analyses revealed the role of leptin gene polymorphisms on the concentration of circulating leptin [2,3] and on the yield and quality traits of meat and milk obtained from farm animal species
The choice of using the goat species to evaluate the effects of leptin gene polymorphism on milk traits and blood parameters lies on the results reported in a previous study [13], where a polymorphism at this gene has been studied on cattle, sheep, goats, and buffaloes

Summary

Introduction

Leptin is a protein hormone secreted from white adipose tissue. It may affect food intake, body energy homeostasis, and nutrient partitioning between tissues and plays an important role on Animals 2019, 9, 424; doi:10.3390/ani9070424 www.mdpi.com/journal/animalsAnimals 2019, 9, 424 energy metabolism. Leptin is a protein hormone secreted from white adipose tissue It may affect food intake, body energy homeostasis, and nutrient partitioning between tissues and plays an important role on Animals 2019, 9, 424; doi:10.3390/ani9070424 www.mdpi.com/journal/animals. Studies with association analyses revealed the role of leptin gene polymorphisms on the concentration of circulating leptin [2,3] and on the yield and quality traits of meat and milk obtained from farm animal species. Leptin or leptin receptor gene polymorphisms have been shown to affect carcass fatty acid composition [7], milk yield [8], milk fat [9,10], milk protein [9], and milk fatty acid composition [11]. Glantz et al [12]

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