Effects of different dietary sources of vegetable oils on performance, milk composition and fatty acid profile of milk and meat of sheep

Author(s)

Michelle de Oliveira Maia

• Document type: Doctoral Thesis
• Press: Piracicaba.
• Institution: Universidade de São Paulo (USP). Escola Superior de Agricultura Luiz de Queiroz (ESALA/BC)
• Defense date: 2011-08-19

Examining board members

Ivanete Susin; Severino Matias de Alencar; Carla Maris Machado Bittar; Claudio Vaz di Mambro Ribeiro; Saulo da Luz e Silva

• Advisor: Ivanete Susin

Abstract

The objective of this study was to evaluate the performance, milk composition, meat and milk fatty acid profile of ewes and lambs fed diets containing canola oil, sunflower oil or castor oil. Additionally, two metabolism trials were conducted to determine the effects of the diets on nutrient digestibility and ruminal measures. Experiment I: 44 Santa Inês ewes with lambs were allotted in a randomized complete block design and fed a control diet (no oil) containing 50% roughage or diets with the addition of 3% of canola oil, sunflower oil or castor oil. The addition of oil decreased DM intake and increased ether extract intake. However, there was no effect on milk production and lamb performance. The percentage of milk fat and milk total solids increased with castor oil. Diets with canola and sunflower oils decreased short chain fatty acids (FA), medium chain, saturated FA and atherogenicity index; and increased C18:0, C18:1-9, C18:2 cis-9, trans-11 (CLA), C18:1 trans-11, long chain and monounsaturated FA. In addition, these diets increased polyunsaturated:saturated (PUFA:SFA) ratio compared to the control diet. Experiment II: Four ruminally cannulated ram lambs were assigned to a 4 x 4 Latin Square design to determine the effects of the diets used in Experiment I on intake, nutrient digestibility and ruminal measures. There was no difference (P>0.10) on DM intake and nutrient digestibility. The oil addition increased pH values and decreased short chain FA. Experiment III: the objective was to evaluate the performance of 36 crossbred Dorper x Santa Inês lambs fed diets with 90% concentrate hay with 3% canola oil, sunflower oil or castor oil. There was no difference on DM intake, average daily gain (ADG) and feed conversion, with average across diets of 957.7 g, 326.4 g and 3.0 kg DMI/kg ADG, respectively. These diets were also evaluated in four ruminally cannulated ram lambs in a 4x4 Latin Square design. There was no difference in DM intake, nutrient digestibility, nitrogen metabolism and ruminal measures, with the exception for ammonia concentration that decreased with oil addition. In the Experiment IV were determine: carcass characteristics, Longissimus dorsi fatty acid profile and physical-chemical composition of the lambs used in Experiment III. The diet with castor oil increased meat ether extract. Sunflower diet decreased C18:1-9 and increased concentrations of C18:1 trans. Castor oil decreased the concentration of C18:2 and PUFA:SFA ratio compared to canola and sunflower oils. Canola and sunflower decreased the concentration of C16:0, increased the concentration of C18:2 cis-9, trans-11 (CLA) and C18:3 -6. Canola oil increased the concentration of C18:3 -3 and sunflower oil increased 6:3 ratio compared to castor oil. (AU)