## 4 Discussion  
The increased content of essential fatty acids (EFA) such as ALA, CLA, and n3 fatty acids in the fat of sheep's milk improves the FA profile and makes it healthier by reducing SFA and increasing UFA. Among the alternatives considered, supplementing animal diets with oils rich in MUFA and PUFA is one of the strategies that has yielded the most interesting results. From this point on, the central theme of this work is to determine the change in milk's fatty acid profile due to the dietary content of different PUFA levels during the lactation stage [19]. However, studies in sheep [27; 28; 29] and cows [30] when fed diets high in LA showed no adverse changes in rumen microbial activity, milk yield, and milk composition. In the current study, a trend toward the higher production of fat and total solids (\(p<0.05\)) was observed in the milk composition of TR-fed ewes. This increase in productivity could be due to the higher fiber content of the fed ration, which provides an optimal environment for digestion in the rumen (higher pH values), resulting in higher acetic acid production, promoting lipogenic metabolic pathways, and resulting in a higher milk fat content [11]. These results are similar to those of [PERSON] et al. [31], where high forage feeding in dairy sheep had a positive influence on the fat content of the milk compared to concentrated feed. By contrast, the protein content of Najdi ewe's milk increased significantly (\(p<0.05\)) when fed the TMR3 diet and decreased when fed the TR diet. This result is consistent with results reported in dairy sheep, where reduced protein content (\(p<0.05\)) in the milk is associated with increased forage feed intake [31]. This fact has been described in animal nutrition, possibly due to the rapid fermentation of carbohydrates and the production of propionate and microbial proteins. This leads to an increasing insulin concentration, milk, and milk protein [32]. Another result was found in the study of Najdi sheep, where milk proteins were higher in ewes that consumed more forage feed [33]. It is worth noting that the SCC was below the natural range of 800,000/mL, meaning that the SCC decreased, and the ewes were free of udder mastitis. This result reported by [34] shows that an oil-containing diet in sheep and goat's milk showed promising results when reducing SCC. As a result of feeding, the main changes in the milk lipid FA profile of Najdi dairy sheep fed with TMR1 increased (\(p<0.05\)) in LA, CLA, C15:0, C15: iso, n3, and PUFA. By contrast, the content of long-chain fatty acids (LCFA), such as stearic acid and oleic acid, increased (\(p<0.05\)) in Najdi dairy sheep fed TR. \begin{table} \begin{tabular}{l c c c c c} \hline \hline \multirow{2}{*}{**FA Groups 1**} & \multicolumn{3}{c}{**Stage of Lactation 2**} & \multirow{2}{*}{**SEM**} & \multirow{2}{*}{**\(p\) Value 3**} \\ \cline{2-2} \cline{4-5}  & **First** & & & & \\ \hline SFA & 65.34 & 70.20 & 69.09 & 2.26 & 0.26 \\ UFA & 34.69  & 30.63  & 27.37  & 1.33 & 0.002 \\ MUFA & 30.17  & 26.21  & 23.71  & 1.42 & 0.001 \\ PUFA & 4.58  & 3.75  & 3.55  & 0.24 & 0.004 \\ n6 & 3.34 & 2.98 & 2.97 & 0.14 & 0.09 \\ n3 & 1.28 & 1.33 & 1.24 & 0.08 & 0.81 \\ n6/n3 & 2.94 & 5.61 & 2.45 & 0.23 & 0.20 \\ OCFA & 3.42 & 3.16 & 3.13 & 0.23 & 0.60 \\ AI & 2.66  & 3.62  & 3.35  & 0.22 & 0.01 \\ TI & 1.34 & 1.53 & 1.60 & 0.12 & 0.37 \\ HFA & 45.07 & 46.36 & 48.25 & 2.17 & 0.54 \\ \hline \hline \end{tabular}   
This result could be caused by the entry of large amounts of 18-carbon fatty acids into the mammary gland, as reported by [PERSON] et al. [35], where LCFA could inhibit the enzymatic activities involved in the de novo synthesis of short and medium-chain fatty acids, particularly acetyl-CoA carboxylase. On the other hand, the high content of stearic acid in milk fat could be a consequence of rumen hydrogenation for OA contained in the rations, depending on the physiological conditions of the rumen [12].