RESUMO

Grooming is a natural hygienic behaviour of cats that favours the formation of hairballs. Increased fibre concentration in the diets is a strategy to minimize hairball formation, but it is not fully effective. Because cat hair is formed mostly by keratin, the addition of keratinases in the diets might be an alternative for hairball control. Thus, the objective was to evaluate the effect of the combined use of sugarcane fibre and a protease complex to reduce the hairball excretion in cats. Twenty-four adult cats were divided into four treatment groups (n = 6 per treatment) in a 2 × 2 factorial arrangement. Treatments were as follows: control diet (Control; containing low concentration of insoluble fibre, 5.34% of total dietary fibre), control diet plus enzyme (Co-e), high-fibre diet (HF; containing high amounts of insoluble fibre, 17.8% of total dietary fibre), and HF diet plus enzyme (HF-e). Proteases from Bacillus licheniformis PWD-1 were administered orally (5 mg/day) as gastro-resistant capsules. Total collection of faeces was carried out to determine the number of excreted hairballs and the coefficient of total tract apparent digestibilities (CTTAD) of the diets. Separate addition of insoluble fibre (HF; p = .5947) or enzyme complex (Co-e; p = .3633) had no effect on the hairballs excreted in the faeces. However, the combined use of insoluble fibre and enzymes (HF-e) reduced (p = .0344) the total number of hairballs excreted. The size distribution of hairballs (small, medium, or large) was not affected by treatments (p = .3763). The CTTAD of crude protein was not affected by protease addition (p = .781) but was reduced by HF and HF-e treatments. Sugarcane fibre associated to keratinolytic enzymes reduces the hairball excretion in cats. This strategy can be adopted for this purpose; however, methods for faecal hairball quantification must be improved. If you have not already completed a Copyright Transfer Agreement, please log on to Wiley Author Serivices, https://authorservices.wiley.com/bauthor/, sign-in and complete the License Agreement form".

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RESUMO

The biomass productivity and nutrient composition of microalgae, such as Chlorella vulgaris, depend on the cultivation process and the nutrient content of growth media. Thus, in this study aimed to investigate the biomass productivity of C. vulgaris cultivated in fish and dairy cattle wastewaters. Thirty wastewater samples (2.5 L) were collected from system of production. Microalgae were cultivated in Erlenmeyer flasks containing 10 mL of microalgae and 1,790 mL of wastewater under constant light of 5,000 lux for 16 days at 25 ± 2.0 °C. Wastewater samples differed in composition. Biomass productivity was 47 % higher (P < 0.0001) in dairy cattle than in fish wastewater, reaching 67.61 g m−3 day−1 (dry matter basis, DM) when compared by Student's t-test (P < 0.05). Cultivation media also had an effect on biomass chemical composition. The C. vulgaris grown in dairy cattle wastewater was higher in crude protein and ash contents (359.6 g kg−1 DM and 230.4 g kg−1 DM, respectively), whereas microalgae grown in fish wastewater had higher nitrogen-free extract content (347.8 g kg−1 DM). Crude fat content did not vary greatly (mean of 313.15 g kg−1 DM). The pH (8.0 ­ 8.7) and ammonia concentration (0.07 to 0.4 mg L−1) in fish wastewater was stable throughout the 16-day experimental period. In dairy wastewater, pH increased up (6.3 to 8.9) to the fourth day and remained constant thereafter, and ammonia concentration increased up (24.3 to 28.7 mg L−1) to the eighth day and then it declined (2.1 mg L−1). The C. vulgaris was successfully grown in both wastewaters, but productivity was higher in dairy cattle wastewater(AU)

A produtividade e a composição de nutrientes da biomassa oriunda de microalgas, como Chlorella vulgaris, dependem do processo de cultivo e do teor de nutrientes dos meios de crescimento. Assim, este estudo teve como objetivo investigar a produtividade de biomassa de C. vulgaris cultivada em águas residuais da criação de peixes e de gado leiteiro. Trinta amostras (2.5 L) foram coletadas dos sistemas de produção. As microalgas foram cultivadas em frascos de Erlenmeyer contendo 10 mL de microalgas e 1,790 mL de águas residuais sob luz constante de 5,000 lux por 16 dias a 25 ± 2,0 ° C. As amostras de águas residuais diferiram na composição. A produtividade de biomassa foi 47% maior (P < 0,0001) nas águas residuais de produção de bovinos leiteiros do que de peixes, atingindo 67,61 g m-3 dia-1 (base de matéria seca, MS) quando comparada pelo teste t de Student (P < 0,05). O meio de cultivo também afetou a composição química da biomassa. C. vulgaris cultivado em águas residuais de gado leiteiro teve maiores teores de proteína bruta e cinzas (359,6 g kg-1 MS e 230,4 g kg-1 MS, respectivamente), enquanto microalgas cultivadas em águas residuais de criação de peixes apresentaram maior teor de extrativo não nitrogenado (347,8 g kg−1 DM). O teor de extrato etéreo não variou (média de 313,15 g kg-1 MS). O pH (8,0 a 8,7) e a concentração de amônia (0,07 a 0,40 mg L−1) as águas residuais dos peixes permaneceram estáveis ao longo do período experimental de 16 dias. Nas águas residuais de laticínios, o pH aumentou (6,3 para 8,9) até o quarto dia e permaneceu constante a partir de então, e a concentração de amônia aumentou até o oitavo dia (24.3 to 28.7 mg L−1) e então declinou (2.1 mg L−1). A C. vulgaris foi cultivada com sucesso em ambas as águas residuais, mas a produtividade foi maior nas águas residuais de gado leiteiro.(AU)

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