Prevention of obesity related disorders in pets by bioactive compounds from chicken by-products

The Norwegian chicken industry annually generates several thousand tons of by-products after fileting and deboning operations. Present utilization is limited to meat meal production and low-value feed applications. However, residual meat on the chicken bones represent a large resource for the manufacture of novel food an feed ingredients as peptides with bioactive properties. Enzymatically digested protein (protein hydrolysate) produced from chicken bones was recently shown to reduce plasma lipids in animals [1], and several studies on fish hydrolysate has shown positive health effects on body weight, plasma lipids, inflammation and atherosclerosis [2-6]. The mechanisms behind these observations are still not known but might be linked to the amino acid composition of short peptide residues. Combined with the utilization of modern enzyme technology and downstream processing, these findings represent a potential cost effective industrial route for the utilisation of chicken by-products in the manufacture of bioactive peptides as novel pet food ingredients. Norilia AS is currently building a plant to process chicken bones by enzymatic hydrolysis. The plant will start production in 2018. The goal of the project was to explore the potential of chicken bones as the base raw material to produce liquid or dried peptide hydrolysate with high quality and high value applications. SINTEF, one of the partners of the project produced four different chicken peptide hydrolysates (CPH) by enzymatic hydrolysis using four different enzymes. Alcalase, Protamex, Corolase PP and a mixture of Papain and bromelain were tested. The CPH were high in protein (84 ? 85 %) with a good amino acid composition. No significant difference was shown in CPH yield and protein content between the CPHs. To determine their health effects, diets containing the four CPHs were investigated in an obesity model in mice compared to a standard control diet. As mitochondrial function and fat burning capacity is important in the prevention of obesity related diseases, including atherosclerosis, we investigated if the CPHs had an effect on mitochondria. Two of the CPHs increased the mitochondrial fat burning in liver of mice, and had a strong anti-inflammatory effect. Thus, the CPHs may contain mitochondria-targeted peptides with anti-atherogenic potential. We examined the effect of diets with these two CPHs on atherosclerotic plaque development in apolipoprotein E-knockout (apoE-KO) mice. After 12 weeks, a significantly lower plaque level was observed in the aorta of CPH-fed apoE-KO mice compared to controls. Interestingly, as the plasma cholesterol and triglyceride level remained constant, this could be due to the anti-inflammatory effect of the CPHs. In summary, one of the CPHs was shown to have the strongest anti-inflammatory and anti-atherogenic potential. In a modern household, many pets suffer from obesity due to a combination of low physical activity and overfeeding, potentially leading to tissue dysfunction and disease. The adipose tissue is highly involved in the development of metabolic disorders such as cardiovascular disease (CVD) and type 2 diabetes mellitus (T2DM). It is the body's largest storage site for triglycerides and plays an important role in regulating the energy metabolism. Therefore, we investigated whether a CPH-diet could reduce the adipose tissue mass and plasma lipids in silver foxes, which is an animal model very relevant for pets. We investigated the effect of two different doses of CPH (30 and 60 % of dietary protein) compared to unhydrolysed chicken filet, and a low-cost poultry meal. CPH tended to reduce the perirenal adipose tissue mass (p<0.08) and this was associated with a significantly increase in markers for mitochondrial fat burning compared to poultry meal. Mitochondrial function can influence plasma lipid levels, and interestingly, the plasma levels of triacylglycerol, free fatty acids and cholesterol, in particular LDL-cholesterol (the bad cholesterol), were lowered by the CPH diet. This effect was observed with both doses of CPH tested, indicating that a low dose (30% of the total protein) is sufficient to give beneficial health effects in larger animals. The CPH did not influence the total body fat deposition, which was similar for all diets. In summary, a method for high-quality CPH production was developed and health effects of CPH diets evaluated. The CPHs-diets tested had high digestibility and although they did not reduce weight gain in obesity models, the animals were healthier with a lower systemic inflammation level and reduced atherosclerosis development. This may have been linked to an improved mitochondrial function in CPH-fed animals.

This project is addressing the potential obesity-reducing effects of bioactive compounds from meat on chicken bones and wings. These bioactive compounds will include short peptide residues. The goal of the project is to explore the potential of chicken bo ne cake as the base raw material to produce liquid or dried peptide hydrolysate with high quality and high value applications, primarily for the pet food industry. It is hypothesized that these compounds may attenuate risk factors for disease due to me tabolic properties such as - Increased energy expenditure - Decreased plasma lipids - Attenuation of oxidative stress - Decrease in obesity related inflammation A range of tasks will be conducted: The project will identify, characterize and quantitate processed peptides from chicken by-products. Enzymatic breakdown of proteins will be based on a combination of endo- and exopeptidases that will result in acceptable sensory as well as functional and physicochemical properties. Laboratory scale optimiza tion trials based on factorial design experiments will be applied to identify the best process conditions. Based on the properties of the produced hydrolysates, optimal process conditions will be chosen and tested in pilot and industrial scale. The metab olic effects of chicken meat peptides will then be studied in vivo by utilising animal models for metabolic diseases. A range of -omics platforms will be applied to assess and integrate the effects on metabolic pathways in liver, muscle and adipose tissue in these models. The anticipated result from the project will be to demonstrate that chicken bones and wings can be used as a starting material for the production of bioactive compounds that can be used in obesity reduction diets for pets. Given a succe ss in the pet feed market and good scientific documentation we expect to start working at the markets for human products. We foresee an even higher potential on this market in the use of functional proteins/peptides