Abstract
Background:
People are increasingly attentive to the quality of the hair of pets. Supplementation with polyunsaturated fatty acid (PUFA) may influence pet hair condition.

Aim:
This study focuses on examining the effect of PUFA-rich oil supplementation on hair improvement and overall health in cats and dogs.

Methods:
We investigated the effects of PUFA supplementation on hair improvement using a mixture of Hoki oil, flax seed oil, lecithin, mussel oil, and sunflower seed oil. The composition of fatty acids in the oil was determined by capillary gas chromatography method. The ω-3 to ω-6 ratio in oil for dogs is 1:4.7, and 1:0.9 for cats. A total of 10 healthy adult cats and 12 healthy adult dogs were enrolled in this 168-day (84 days each) cross-over design trial. At the end of each period, serum was obtained from the animals via anterior limb vein blood collection for testing of blood lipids, antioxidant capacity, and inflammation-related factors. Body weight, fecal scoring, and hair condition were also recorded in this test.

Results:
Dog food (0.70 mL/kg BW) and cat food (0.75 mL/kg BW) high PUFA oil supplementation improved flexibility, brightness, and skin condition scores in both cats and dogs (p< 0.05). Additionally, the breaking force of hair increased by 5.79% in cats and 8.68% in dogs respectively. The images acquired by scanning electron microscopy (SEM) show the mechanism may be related to alterations in the microstructure of hair. This study also showed that moderate PUFA supplementation didn’t result in weight gain or changes in fecal scoring (p > 0.05); however, triglyceride levels increased by 13.16% in cats and by 33.33% in dogs (p< 0.05), while the levels of Tumor Necrosis Factor-alpha /TNF-ɑ significantly decreased (p< 0.05).

Conclusion:
PUFA supplementation effectively enhances hair quality in companion animals but may elevate serum triglyceride levels. Thus, dosage and fatty acid composition in dietary formulations should be carefully considered.

Key words: Cat; Dog; Hair; Lipid; Polyunsaturated fatty acid.