MILK FATTY ACID COMPOSITION AS A RESPONSE TO DIETARY N-3 FATTY ACIDS IN HOLSTEIN DAIRY COWS

P.A. Vlaicu, Tatiana Dumitra Panaite, Raluca Paula Turcu, I. Voicu, Mariana Ropotă, Margareta Olteanu, I. Stănel

Abstract
   Flax meal is known for its high content of alpha-linolenic acid, widely used as a source of fatty acid n-3 in animal feed. In this regard, a study on dairy cows was carried out to assess the influence of the use of flax meal on milk fatty acids. 15 dairy cows, Holstein breed (50 ± 23 days in lactation), with an average weight of 580 ± 37 kg, were divided into 3 experimental groups (C, E1, E2). Cows, were fed 2 times/day, and received a basic concentrate mix (corn, soybean meal, sunflower meal and wheat bran) and roughage (alfalfa hay and maize silo). Group C received the basic concentrate, while groups E1 and E2 received different formulations of concentrate by substituting sunflower meal (12%) for both groups (E1, E2). Besides, in the E2 group concentrate the wheat bran was substituted with barley rootlets (17.30%). Milk samples were collected in the morning and evening for a period of five consecutive days, on which the determinations of fatty acids were made using the chromatographic gas method. The use of flax meal in cows feeds resulted significant increase (P <0.05) in milk cows a of n-3 fatty acids at the end of the experiment for both groups fed flax meal, in the morning 0.53% and 0.54% in the evening (E1) 0.49% in the morning and 0.53% in the evening (E2) versus the C group (0.23%), representing a good source of omega 3. Such data indicated that the fatty acid addition was favourable to the fatty alpha-linolenic acid in milk.

Key words: n-3 fatty acids, milky cows, flax meal, barley rootlets

COMPOZIŢIA ACIZILOR GRAŞI DIN LAPTE CA RASPUNS AL RAŢIILOR BOGATE ÎN ACIZI GRAŞI N-3 PENTRU VACILE DE LAPTE HOLSTEIN

P.A. Vlaicu, Tatiana Dumitra Panaite, Raluca Paula Turcu, I. Voicu, Mariana Ropotă, Margareta Olteanu, I. Stănel

Rezumat
   Srotul de in este cunoscut pentru conţinutul mare de acid alfa-linolenic, folosit pe scară largă ca sursă de acid gras n-3 in alimentatia animalelor. In acest sens, s-a realizat un studiu pe vaci de lapte pentru a evalua influenta utilizarii srotului de asupra acizilor grasi din lapte. 15 vaci de lapte, rasa Holstein (50 ±23 zile la lactaţie), cu o greutate medie de 580 ±37 kg, au fost divizate în 3 loturi (5vaci/ grup) experimentale (C, E1, E2),. Vacile, furajate de 2 ori/zi, au primit un amestec concentrat de baza (porumb, srot de soia, srot de floarea soarelui si tarate de grau) si furaj grosier (fan de lucerna si siloz de porumb). Lotul C a primit concentratul de baza, in timp ce loturile E1 si E2 au primit formule diferite de concentrat, prin substituirea srotului de floarea soarelui (12%) pentru ambele loturi (E1, E2). Fata de E1, in concentratul lotului E2 si tarata de grau a fost substituita cu radicele de orz (17.30%). Probele de lapte au fost recoltate dimineata si seara pe o perioada de cinci zile consecutive, pe care s-au facut determinări de acizii graşi folosind metoda gaz cromatografica. Utillizarea srotului de in in hrana vacilor de lapte a determinat cresterea semnificativa (P <0,05) a acizilor grasi n-3 la finalul experimentului în laptele ambelor loturi furajate cu srot de in 0.53% dimineata si 0.54% seara (E1) respectiv cu 0.49% dimineata si 0.53% seara (E2) fata de lotul M (0.23%), reprezentand o buna sursa de omega 3.

Cuvinte cheie: n-3 acizi graşi, vaci de lapte, srot de in, calitate lapte