Effect of feeding lambs with cottonseed co-products on reproductive system and meat quality

Author(s)

Tiago do Prado Paim

• Document type: Master's Dissertation
• Press: Piracicaba.
• Institution: Universidade de São Paulo (USP). Centro de Energia Nuclear na Agricultura (CENA/STB)
• Defense date: 2012-12-07

Examining board members

Helder Louvandini; Dante Pazzanese Duarte Lanna; Eliane Sayuri Miyagi

• Advisor: Helder Louvandini

Abstract

The aim of this study was to investigate the effect of feeding cotton co-products with different gossypol concentrations on reproductive development of lambs close to puberty and also on carcass traits and fatty acid profile of meat. Twenty four 5-months old ram lambs (20.6 ± 1.9 kg BW) were used. These were housed in individual pens and received four diets: 20% of dry matter intake (DMI) of whole cottonseed (WCS), 20%DMI of cottonseed meal (CSM), 20%DMI of high oil cottonseed meal (CSC) and a control group without cottonseed co-products (CTL). Free gossypol intake was 0, 16.32, 6.98 and 5.47 mg/kgBW for CTL, WCS, CSC and CSM, respectively. At each 15 days, the animals were weighted, and blood and semen samples were collected. Sperm motility, vigor, mass movement, concentration and pathologies were evaluated. The free testosterone and cortisol concentrations in serum were determined. After 95 experimental days, the lambs were slaughtered and carcass traits were measured. Meat samples of Longissumus dorsi muscle were taken for fatty acid profile analysis. And testis samples were collected to analysis in light and transmission electron microscopes. The treatments did not differ in average daily weight gain, sperm volume, motility, vigor and concentration. The CTL group had higher testosterone concentration than CSC at the end of trial and had lower total sperm defects and higher mass movement than others. The number of mitochondrial sheath aplasia increased with increasing gossypol level in diet. There was no relation between the other variables evaluated and gossypol level in diets; however the groups that received cottonseed co-products showed worse reproductive parameters than CTL. Therefore, these co-products had negative impact on reproductive system of puberal lambs. In relation to fatty acid profile, meat from CSM and CSC groups had higher levels of conjugated linolenic acid (CLA) than others and yet CSC group showed higher vaccenic acid than others. Meat from animals that received whole cottonseed had less unsaturated fatty acids, CLA and vaccenic acid. Therefore, between cotton co-products, the processed (CSM and CSC) must be preferred for use in ruminant feed rather than whole cottonseed. The meat from animals that did not receive cotton co-products had higher n-3 fatty acid, and also better n-6 to n-3 ratio compared to others. This can impair the use of these co-products due to current great importance given to these fatty acids in human nutrition (AU)

• FAPESP's process: 10/14236-8 - Development of reproductive system of Santa Inês lambs fed with co-products of cotton (Gossypium spp.)
• Grantee: Tiago do Prado Paim
• Support Opportunities: Scholarships in Brazil - Master