Resistant starch (RS) is highly fermentable by microbiota in the colon, resulting in the production of SCFAs. RS is thought to mediate a large proportion of its health benefits, including increased satiety, through the actions of SCFAs. The aim of this study was to investigate the effects of a diet high in RS on luminal microbiota composition, luminal SCFA concentrations, and the expression of host genes involved in SCFA uptake, SCFA signaling, and satiety regulation in mucosal tissue obtained from small intestine, cecum, and colon. Twenty adult female pigs were either assigned to a digestible starch (DS) diet or a diet high in RS (34%) for a period of 2 wk. After the intervention, luminal content and mucosal scrapings were obtained for detailed molecular analysis. RS was completely degraded in the cecum. In both the cecum and colon, differences in microbiota composition were observed between DS- and RS-fed pigs. In the colon these included the stimulation of the healthy gut-associated butyrate-producing Faecalibacterium prausnitzii, whereas potentially pathogenic members of the Gammaproteobacteria, including Escherichia coli and Pseudomonas spp., were reduced in relative abundance. Cecal and colonic SCFA concentrations were significantly greater in RS-fed pigs, and cecal gene expression of monocarboxylate transporter 1 (SLC16A1) and glucagon (GCG) was induced by RS. In conclusion, our data show that RS modulates microbiota composition, SCFA concentrations, and host gene expression in pig intestine. Combined, our data provide an enhanced understanding of the interaction between diet, microbiota, and host.

Insects have been proposed as a high-quality, efficient and sustainable dietary protein source. The present study evaluated the protein quality of a selection of insect species. Insect substrates were housefly pupae, adult house cricket, yellow mealworm larvae, lesser mealworm larvae, Morio worm larvae, black soldier fly larvae and pupae, six spot roach, death's head cockroach and Argentinean cockroach. Reference substrates were poultry meat meal, fish meal and soyabean meal. Substrates were analysed for DM, N, crude fat, ash and amino acid (AA) contents and for in vitro digestibility of organic matter (OM) and N. The nutrient composition, AA scores as well as in vitro OM and N digestibility varied considerably between insect substrates. For the AA score, the first limiting AA for most substrates was the combined requirement for Met and Cys. The pupae of the housefly and black soldier fly were high in protein and had high AA scores but were less digestible than other insect substrates. The protein content and AA score of house crickets were high and similar to that of fish meal; however, in vitro N digestibility was higher. The cockroaches were relatively high in protein but the indispensable AA contents, AA scores and the in vitro digestibility values were relatively low. In addition to the indices of protein quality, other aspects such as efficiency of conversion of organic side streams, feasibility of mass-production, product safety and pet owner perception are important for future dog and cat food application of insects as alternative protein source.

To meet the projected substantial growth in the global demand for meat, we are challenged to develop additional protein-rich feed ingredients while minimizing the use of natural resources. The larvae of the black soldier fly (BSF) have the capacity to convert low-value organic resources into a high quality protein source for pigs, chickens and fish and as such may increase both the productivity and the efficiency of the food chain. The aim of this study was to assess the environmental opportunities of BSF larvae reared on different sources using up to date literature data on the efficiency of BSF larvae in converting such resources into biomass. The current EU legislative framework was used to classify the various resources for rearing insects. Data of forty articles published until 1 September 2017 were used, reporting on in total 78 (mixtures of) resources used for growing BSF larvae. Data on the resource conversion efficiency on dry matter (DM) and N basis was presented in 11 and 5 studies, evaluating 21 and 13 resources, respectively. Resources studied included food and feed materials (A, n=8 resources), foods not intended (anymore) for human consumption (B1, n=4), and residual streams such as food waste (D, n=2), and animal manure (E, n=7).Conversion efficiency varied from 1.3 to 32.8% for DM and from 7.4 to 74.8% for N. Using life cycle assessment, our environmental results showed that resources within the legal groups (i.e. A and B1) that are, at the moment, not allowed in EU as animal feed have in general a lower impact in terms of global warming potential, energy use, and land use. On a per kg protein basis, BSF larvae reared on a resource that contains food (e.g. sorghum) and feed (e.g. dried distillers grains with solubles) products generally have higher environmental impacts than conventional feed protein sources (fishmeal and soybean meal). Using insects as feed, therefore, has potential to lower the environmental impact of food production but a careful examination of the resource is needed in terms of environmental impact, safety and economics.

Cats are strict carnivores and in the wild rely on a diet solely based on animal tissues to meet their specific and unique nutritional requirements. Although the feeding ecology of cats in the wild has been well documented in the literature, there is no information on the precise nutrient profile to which the cat's metabolism has adapted. The present study aimed to derive the dietary nutrient profile of free-living cats. Studies reporting the feeding habits of cats in the wild were reviewed and data on the nutrient composition of the consumed prey items obtained from the literature. Fifty-five studies reported feeding strategy data of cats in the wild. After specific exclusion criteria, twentyseven studies were used to derive thirty individual dietary nutrient profiles. The results show that feral cats are obligatory carnivores, with their daily energy intake from crude protein being 52 %, from crude fat 46 % and from N-free extract only 2 %. Minerals and trace elements are consumed in relatively high concentrations compared with recommended allowances determined using empirical methods. The calculated nutrient profile may be considered the nutrient intake to which the cat's metabolic system has adapted. The present study provides insight into the nutritive, as well as possible non-nutritive aspects of a natural diet of whole prey for cats and provides novel ways to further improve feline diets to increase health and longevity. Key words: Cats: Nutrient profile: Natural diet: MetabolismThe domestic cat (Felis silvestris catus) is adopted as a pet in millions of homes and can be considered one of the most popular pet animals worldwide. Cats were domesticated approximately 9000-10 000 years ago in the Near East (1) and are thought to originate from at least five distinctive subspecies of F. silvestris from across the Near East region, namely F.s. silvestris, F.s. lybica, F.s. ornate, F.s. cafra and F.s. bieti (1) . After domestication, descendants were dispersed across the world with human assistance, and gave rise to today's domestic cat. A small subset of these domesticated cats has undergone intensive selection directed at specific aesthetic traits, leading to the development of so-called pedigree cats. Nowadays, forty-one breeds are recognised by the Cat Fanciers' Association, including sixteen 'natural breeds' (2) . These natural breeds are thought to be regional variants originating from domesticated F. silvestris subspecies (3) .The initiation of domestication of wildcats is believed to have coincided with the change from the hunter-gatherer lifestyle of man in the Palaeolithic to the agricultural lifestyle in the Fertile Crescent about 12 000 years ago (1,4) . The permanent human settlements stored grains and middens, providing a new ecological niche for commensal species such as mice and rats. These rodents became peridomestic and provided a reliable food source for native wildcats. Wildcats then became adapted to the urban environment and became commensals like rodents (5) . Wildcats in the urban...

BackgroundDietary fibers contribute to health and physiology primarily via the fermentative actions of the host’s gut microbiome. Physicochemical properties such as solubility, fermentability, viscosity, and gel-forming ability differ among fiber types and are known to affect metabolism. However, few studies have focused on how they influence the gut microbiome and how these interactions influence host health. The aim of this study is to investigate how the gut microbiome of growing pigs responds to diets containing gel-forming alginate and fermentable resistant starch and to predict important interactions and functional changes within the microbiota.ResultsNine growing pigs (3-month-old), divided into three groups, were fed with either a control, alginate-, or resistant starch-containing diet (CON, ALG, or RS), and fecal samples were collected over a 12-week period. SSU (small subunit) rDNA amplicon sequencing data was annotated to assess the gut microbiome, whereas comprehensive microarray polymer profiling (CoMPP) of digested material was employed to evaluate feed degradation. Gut microbiome structure variation was greatest in pigs fed with resistant starch, where notable changes included the decrease in alpha diversity and increase in relative abundance of Lachnospiraceae- and Ruminococcus-affiliated phylotypes. Imputed function was predicted to vary significantly in pigs fed with resistant starch and to a much lesser extent with alginate; however, the key pathways involving degradation of starch and other plant polysaccharides were predicted to be unaffected. The change in relative abundance levels of basal dietary components (plant cell wall polysaccharides and proteins) over time was also consistent irrespective of diet; however, correlations between the dietary components and phylotypes varied considerably in the different diets.ConclusionsResistant starch-containing diet exhibited the strongest structural variation compared to the alginate-containing diet. This variation gave rise to a microbiome that contains phylotypes affiliated with metabolically reputable taxonomic lineages. Despite the significant microbiome structural shifts that occurred from resistant starch-containing diet, functional redundancy is seemingly apparent with respect to the microbiome’s capacity to degrade starch and other dietary polysaccharides, one of the key stages in digestion.Electronic supplementary materialThe online version of this article (doi:10.1186/s40168-015-0078-5) contains supplementary material, which is available to authorized users.