Modification of milk fatty acid composition by feeding forages and agro-industrial byproducts from dry areas to Awassi sheep

Abstract

The study tested the hypothesis that certain underused forages and agro-industrial byproducts available in dry areas may positively influence fatty acid (FA) composition and antioxidative properties of milk by their contents of residual oil or phenolic compounds or both. Sixty multiparous fat-tailed Awassi ewes were allocated to 6 groups in a completely randomized block design. During 50 d, the ewes were group-fed 2.5 kg of dry matter/d per ewe 1 of 6 isonitrogenous and isoenergetic diets (forage:concentrate, 0.3:0.7). The test feeds, comprising 30% of the diets, replaced either barley straw [lentil straw, olive leaves, and Atriplex (saltbush) leaves, rich in phenolic compounds or electrolytes] or conventional concentrate ingredients (olive cake and tomato pomace; ∼10% lipids) from the control diet. The diets containing olive cake and tomato pomace were rich in oleic acid (18:1 cis-9; 27% of total dietary FA) and linoleic acid (18:2 cis-9,cis-12; 37%), respectively. Profiles of FA were determined in individual milk samples drawn on d 0 and in wk 1, 3, 5 and 7. Data was analyzed by repeated measurement analysis. No consistent treatment effects on yield and gross nutrient composition of the milk were observed, although some differences occurred. Milk resulting from the Atriplex leaf diet expressed the highest antiradical activity, which was low with control and olive leaves. Feeding the tomato pomace and olive cake diets decreased the proportions of short- and medium-chain FA, whereas oleic acid clearly increased in proportion to total FA. Olive leaves most effectively increased rumenic acid (18:2 cis-9,trans-11) and α-linolenic acid (18:3 cis-9,cis-12,cis-15) in milk fat. This also resulted in the highest α-linolenic acid transfer rate from feed to milk and suggests that olive leaves affect ruminal biohydrogenation at several steps. Several alternative feeds exist with an added value, as they enhance FA with potential health benefits and the stability of the milk with higher antioxidative activity, even though responses to test feeds differed largely. It remains to be investigated whether combinations of these feeds would be complementary in these beneficial effects.

Performance and milk composition of dairy goats as affected by the dietary level of stoned olive cake silages

“…The main effects of OCS on FA composition of milk fat were decreased total SFA, but increased MUFA as reported for sheep [1–4] and for goats [7]. The only increase in individual SFA by feeding OCS was in C18:0 and this was in line with the other works [1–4].…”

“…Alternatively this FA, rich in OCS, can be directly incorporated in the mammary gland. Similar to the results, Abbeddou et al [3–4] and Gómez-Cortés et al [23], who included supplementary olive oil to ewe’s diet, reported that C18:2c9 proportions were lower in milk fat of goats that were fed TMR containing OCS. This could have resulted from the different ingredients of TMR, even when OCS was replaced with mostly barley in the control diet, and thereby had a probable lower content of linoleic acid in TMR.…”

“…While, this effect was unequivocally observed with sheep [1–4], it was not evident with buffalos [5], camel [6] and goat [7] probably due to insufficient inclusions of OC to the diets. Moreover, the inconsequential responses to feeding OC on the yield parameters of dairy ruminants suggest that both milk quality and animal performance could be affected by the dietary level of OC.…”

Influence of feeding Mediterranean food industry by-products and forages to Awassi sheep on physicochemical properties of milk, yoghurt and cheese

“…On days 0, 24, 36 and 48, morning and afternoon milk was obtained manually for yield recording and sampling purpose (AOAC 968.12). Morning milk samples were analysed on the same day for protein, fat, lactose and total solids (Milkoscan, model 133 B, Foss Electric, Hillerød, Denmark), casein contents (AOAC 927.03) and fatty acid profile (Abbeddou et al 2011c). Electrical conductivity (Microprocessor EC/TDS Meter, HI98360, Hanna Instruments, Padovana, Italy), pH (pH meter, HI113, Hanna Instruments, Padovana, Italy) and density (density meter, DMA35, PAAR, Graz, Austria) were analysed in the same individual milk samples.…”

Fruit and Vegetable Co-Products as Functional Feed Ingredients in Farm Animal Nutrition for Improved Product Quality

“…Laying hens Antioxidant [52] Grape pomace Laying hens Antioxidant [53] Grape seed/ Grape seed extract Laying hens Antioxidant [54] Tomato pulp Quails Antioxidant [55] Tomato powder Quails Antioxidant [56] Tomato powder Quails Yolk colour enhancement [57] Olive pomace Rabbits Antioxidant [58] Tomato pomace Rabbits Improved fatty acid composition [59] Olive Tomato pomace Ewes Improved milk fatty acid composition [63] Olive leaves Ewes Improved milk fatty acid composition [63] Olive cake Ewes Improved milk fatty acid composition [64,65] Tomato waste Goats Improved milk fatty acid composition [66] Pomegranate seed pulp Goats Improved milk fatty acid composition [67] Citrus (orange) pulp Goats Improved appearance, taste and texture (cheese) [68] Pomegranate seed pulp Kids Antioxidant [69] Pomegranate by-product silage Lambs Improved milk fatty acid composition [70] Olive cake Lambs Antioxidant [71] Dried citrus pulp Lambs Antioxidant [72,73] Pomegranate peel extract Cows Improved milk fatty acid composition [74] Dried stoned olive pomace Water buffaloes Improved milk fatty acid composition [75] 1 Function on meat unless otherwise stated.…”