## 3 Results and Discussion  
### Spirulina Effects on Mozzarella Cheese's Chemical Composition  
The milk composition was affected by Spirulina supplementation only in terms of protein, lowering the percentage from 4.59 to 4.31 (SEM 0.07, \(p<0.05\)), while the fat and lactose contents were not influenced by Spirulina inclusion in the buffalo diets. The same trend was observed in the mozzarella cheese's chemical composition; the fat, lactose, and moisture contents were not different among the two groups, while the protein amount was tendentially higher in the C group ((18.01 vs. 17.12 \(\pm\) 0.33%; \(p<0.10\) (mean \(\pm\) SEM)) than the S group. Our results do not agree with the increases in protein, fat, and lactose found by [PERSON] et al. [40] as effects of Spirulina supplementation in cows, and the findings of [PERSON] et al. [41] and [PERSON] et al. [42], who registered an increase in milk fat. Despite the small differences in the protein content, the AA profiles of the mozzarella cheese samples did not change with Spirulina supplementation (Table 3). Among the EAAs, LEU and LYS are the most abundant in both products, tending to be higher in the S samples, which could be due to the AA profile of the added Spirulina. Microalgae in general are good sources of EAAs. The milk from the S group contained 27% more EAAs and 23% more NEAAs than the C group. The presence of EAAs in milk and dairy products, especially branched-chain amino acids, is important in terms of their benefits for human health [43]. Recently, [PERSON] et al. [44; 45] reported interesting results about a possible beneficial effect of delatocsed buffalo milk whey by-product on colorectal human carcinogenesis. It is well known that primary proteolysis occurs during mozzarella processing [46], and the effect of the composition of milk protein fractions (relative contents of alpha S1 casein and beta casein) on milk coagulation properties has been widely studied [47; 48]. Table 4 shows no significant differences in the FA profiles of the mozzarella cheese samples between the C and S groups, nor in the calculated nutritional index. [PERSON] et al. [49] did not observe any significant differences in the dairy cow milk FA content when substituting 5% of soybean meal with Spirulina in their diets, except for the total n-6 FA, which was higher in the control milk samples. This highlights that the diet supplemented with Spirulina lowered the apparent transfer efficiency of the total n-6 FA. In contrast, numerous authors have reported that replacing feed with Spirulina yields a significant improvement in the FA profile of ruminants' milk. [PERSON] et al. [50] examined the effects of three levels of Spirulina substitution (i.e., 5%, 10%, and 15%) in the diets of ewes. Their findings revealed that only the highest level of substitution increased the PUFA and \(\omega\)-3 PUFA contents, while a mere 5% of substitution was adequate to decrease the AI. [PERSON] et al. [51] added 40 g of powdered Spirulina to cow diets and observed a decrease in the SFA amount, while the MUFA and PUFA contents in the milk increased at the 45 th day of experimentation. As stated by many authors, species and breeds strongly affect the animals' responses to diets [14; 15]. This might partially explain why the buffalo mozzarella cheese chemical compositions did not differ among the two groups in our study. Moreover, the amount of Spirulina included in the S diets for the buffalo could be too low to see changes/improvements in the milk and cheese compositions. To date, most of the studies in which microalgae were tested for animal feeding showed inconsistent and contradictory effects, probably due to the high variability among the studies, the doses of microalgae and species, the experimental period, and the percentage of forage in the diet [14]. However, microalgae use in animal feeding originated with the objective of improving the nutritional quality, particularly in terms of the FA profile, of milk and dairy products [15].