Improving the Quality of Milk Fatty Acid in Dairy Cows Supplemented with Soybean Oil and DHA-Micro Algae in a Confined Production System

Abstract

The objective was to reduce saturated fatty acids (SFA) and increase conjugated linoleic acid (CLA, cis-9, trans-11 C18:2), α-linolenic (cis-9, cis-12, cis-15C18:3) and docosahexaenoic (DHA, C22:6) contents in milk from confined dairycows in order to promote a healthier option. The work was carried out in acommercial farm (Talar) located in Laguna del Sauce, Maldonado (Uruguay).Twenty four cows were assigned to one of two treatments (12 cows per treatment) over a 6 weeks experimental period. Treatments consisted in a controltotal mixed ration (C-TMR) without supplementary lipids (L) or the sameTMR with the addition of 0.144 kg/cow∙day of algae and 0.72 kg/cow∙day ofsoybean oil (L-TMR). Chemical composition of the TMR (44.27% DM) averaged 15.94% for crude protein (CP), 38.20% neutral detergent fiber (NDF),20.36% acid detergent fiber (ADF), 5.56% fat, 5.30% ash and 28.6% nonstructural carbohydrate (NSCH) with 1.81 Mcal/kg of net energy for lactation(NEL). After 39 days of feeding, individual milk samples were collected duringthree consecutive days. From the total milk collected, 20 ml were immediatelyused for chemical composition (Milko Scan) and 80 ml for analysis for milkFA profile. From week 3 onwards, milk production (kg/cow∙day) resultedhigher (P < 0.001) in L-TMR (36.9) compared to C-TMR (35.2). At week 6 oftrial, the difference in milk production averaged 5.14% for L-TMR. Supplementary lipids reduced (P < 0.002) milk fat concentration (g/100g) from 3.36in C-TMR to 2.40 in L-TMR without effect (P = 0.43) on milk protein contentHow to cite this paper: Gagliostro, G.A.,Antonacci, L.E., Pérez, C.D., Rossetti, L.and Carabajal, A. (2018) Improving theQuality of Milk Fatty Acid in Dairy CowsSupplemented with Soybean Oil andDHA-Micro Algae in a Confined Production System. Agricultural Sciences, 9,1115-1130.https://doi.org/10.4236/as.2018.99078Received: August 15, 2018Accepted: September 10, 2018Published: September 13, 2018Copyright © 2018 by authors andScientific Research Publishing Inc.This work is licensed under the CreativeCommons Attribution InternationalLicense (CC BY 4.0).http://creativecommons.org/licenses/by/4.0/Open AccessG. A. Gagliostro et al.DOI: 10.4236/as.2018.99078 1116 Agricultural Sciences(C-TMR = 3.20; L-TMR = 3.07 g/100g). Milk lactose (C-TMR = 4.86, L-TMR= 4.69 g/100g) and urea nitrogen contents (C-TMR = 21.18, L-TMR = 17.33g/100g) tended (P < 0.056) to decrease in L-TMR as well as fat corrected milkoutput (C-TMR = 30.89, L-TMR = 29.49 kg/cow∙day, P < 0.098). Lipid supplementation reduced (−23%) milk content of C12:0 to C16:0 FA averaging 45.19in C-TMR and 34.74 g/100g in L-TMR (P < 0.001). The atherogenic index(AI) of milk decreased (P < 0.001) from 2.69 in C-TMR to 1.50 in L-TMR(−44.2%). Concentration (g/100g) of elaidic (C18:1 trans-9) (0.23) and C18:1trans-10 (0.44) FA increased (P < 0.001) in L-TMR milk. Milk vaccenic acid(trans-11 C18:1, VA) increased from 1.08 in C-TMR to 2.56 g/100g of FA inL-TMR (P < 0.001). Milk CLA content (cis-9, trans-11 C18:2) increased (127%)from 0.62 in C-TMR to 1.41 g/100g FA in L-TMR milk. Content ofα-linolenic acid resulted 20% higher (P < 0.001) in L-TMR milk (0.35 g/100gFA) compared to C-TMR (0.30 g/100g FA). Milk DHA increased from 0 inC-TMR to 0.14 g/100g FA in L-TMR. The omega-6/-3 ratio in C-TMR milk(9.61) was reduced (P < 0.001) to 6.78 in L-TMR milk. Milk oleic acid (cis-9C18:1) resulted higher (P < 0.001) in L-TMR (23.65) than in C-TMR (19.75g/100g FA). The nutritional value of milk fat from confined cows was naturally improved by feeding polyunsaturated FA in the ration, obtaining a reduction of saturated FA and increased levels of healthy FA (CLA, DHA andα-linolenic).