Melanocortin receptor accessory proteins (MRAPs) modulate signaling of melanocortin receptors in vitro. To investigate the physiological role of brain-expressed Melanocortin 2 Receptor Accessory Protein 2 (MRAP2), we characterized mice with whole body and brain-specific targeted deletion of Mrap2, both of which develop severe obesity at a young age. Mrap2 interacts directly with Melanocortin 4 Receptor (Mc4r), a protein previously implicated in mammalian obesity, and it enhances Mc4r-mediated generation of the second messenger cyclic AMP, suggesting that alterations in Mc4r signaling may be one mechanism underlying the association between Mrap2 disruption and obesity. In a study of humans with severe, early-onset obesity, we found four rare, potentially pathogenic genetic variants in MRAP2, suggesting that the gene may also contribute to body weight regulation in humans.

Maintenance of glucose homeostasis during late-term embryonic development is dependent upon the amount of glucose held in reserve primarily in the form of glycogen in the liver and upon the degree of glucose generated by gluconeogenesis from protein first mobilized from amnion albumen and then from muscle. Insufficient glycogen and albumen will force the embryo to mobilize more muscle protein toward gluconeogenesis, thus restricting growth of the late-term embryo and hatchling. We hypothesize that administration of available carbohydrates to the amnion will improve glycogen reserves and spare muscle protein mobilization for gluconeogenesis during late-term embryonic and posthatch neonatal development. Our hypothesis was tested by comparing BW gain, liver glycogen reserves, and muscle weight of in ovo fed and control embryos during last days of embryonic incubation until 25 d after hatching. We examined, using 600 birds from 2 different strains of commercial boilers, body and muscle weights and glycogen reserves following feeding embryos at d 17.5 of incubation with a solution containing maltose, sucrose, dextrin, and beta-hydroxy-beta-methylbutyrate (HMB). Providing carbohydrates and HMB to late-term embryos increased hatching weights by 5 to 6% over controls, improved liver glycogen by 2- to 5-fold, and elevated relative breast muscle size by 6 to 8%. These weight advantages were sustained through the end of the experiments at 25 d of age. It is reasonable to assume that the elevated glycogen levels in the in ovo treatment reduce the need to produce glucose via gluconeogenesis and, therefore, contribute to less use of muscle protein and hence a greater percentage of pectoral muscle weight in the in ovo birds.

Four hundred and fifty 1-d-old male Lingnan Yellow broiler chickens were used to investigate the effects of Clostridium butyricum on growth performance, immune function, and cecal microflora. The birds were randomly assigned to 5 treatments and offered the same antibiotic-free basal diets for 42 d. The treatments were as follows: no addition (control), 1 × 10(7) cfu C. butyricum/kg of diet (CB1), 2 × 10(7) cfu C. butyricum/kg of diet (CB2), 3 × 10(7) cfu C. butyricum/kg of diet (CB3), and 10 mg of colistine sulfate/kg of diet (antibiotic). Birds fed either CB2 or antibiotic had greater overall BW than those in the control group. During d 1 to 7, d 21 to 42, and d 1 to 42, birds fed either CB2 or CB3 or the antibiotic diet had greater ADG compared with those in the control group. No significant differences were observed in BW or ADG among the CB2, CB3, and antibiotic groups. Birds fed the CB2 or CB3 diet had greater concentrations of IgA and IgG in the serum from d 14 to 42 and greater IgM in the serum from d 21 to 42 than those in the control group. Birds fed the CB3 diet had a greater concentration of complement component 3 in the serum than those in the control group from d 7 to 42. Dietary C. butyricum decreased (P < 0.05) Escherichia coli in cecal contents on d 14 and 42, and both CB2 and CB3 decreased (P < 0.05) cecal Salmonella and Clostridium perfringen from d 14 to 42 compared with the control. Broilers fed either CB2 or CB3 had greater cecal Lactobacillus and Bifidobacterium counts from d 21 to 42, and birds fed C. butyricum had greater cecal C. butyricum counts during the whole period compared with those in the control group. The results indicate that C. butyricum promotes growth performance and immune function and benefits the balance of the intestinal microflora in broiler chickens.

The effects of 2 levels of mannanoligosaccharide (MOS) in feed were compared with antibiotic growth promoters on growth performance, intestinal morphology, cecal and litter microbial populations, and carcass parameters in broilers raised in a sanitary environment. Dietary treatments included: 1) antibiotic growth promoter-free diet (control), 2) VIRG (diet 1 + 16.5 mg/kg of virginiamycin), 3) BACT (diet 1 + 55 mg/kg of bacitracin), 4) LMOS (diet 1 + 0.2% MOS), and 5) HMOS (diet 1 + 0.5% MOS). Birds were randomly assigned to 3 replicate pens/treatment (n = 55/pen). Body weight and feed intake were recorded weekly throughout 38 d. At d 14, 24, and 34, a 1-cm segment of duodenum, jejunum, and ileum was used in morphological analysis (n = 9 birds/d per treatment). At the same bird ages, cecal contents were assayed for lactobacilli, bifidobacteria, Salmonella, Campylobacter, and Escherichia coli, whereas litter was analyzed for Salmonella, Campylobacter, and E. coli. Carcass yields (breast fillet and tenders, thigh, drumstick, and wing) were determined at d 38. Body weight, feed conversion, and carcass yields did not differ among treatments. In contrast to birds fed VIRG or BACT, LMOS and HMOS consistently increased (P < 0.05) villi height and goblet cell number per villus in all intestinal segments at d 24 and 34. Bifidobacteria concentrations were higher (P < 0.05) in LMOS- and HMOS-fed birds at all time points. Birds and litter from all treatments were free of Salmonella. At d 14 and 24, cecal E. coli and Campylobacter counts were not different among treatments. In comparison to birds fed control, at d 34, BACT, LMOS, and HMOS significantly reduced (P < 0.05) cecal E. coli concentrations, whereas Campylobacter counts were reduced (P < 0.05) by VIRG, BACT, and LMOS. Litter bacterial counts were not altered by dietary treatments. In conclusion, under conditions of this study, MOS conferred intestinal health benefits to chickens by improving its morphological development and microbial ecology. But, there were no additional benefits of the higher MOS dosage.

No abstract

In ovo feeding (IOF), injecting dietary components into the amnion about 1 d prior to internal pipping, may enhance growth by altering glycogen status. This hypothesis was evaluated with 5 IOF solutions containing protein, beta-hydroxy-beta-methylbutyrate (HMB), and carbohydrate. Four IOF treatments were arranged as a factorial of 2 levels of egg white protein (EWP; 0 and 18%) and 2 levels of HMB (0 and 0.1%). An IOF solution of carbohydrates (S; 20% dextrin and 3% maltose) was evaluated for contrast purposes. At 23 d of incubation, 1.5 mL of IOF solution was injected into the amnion of 100 eggs per treatment. At hatch, feed and water were provided ad libitum. At hatch and 3 and 7 d of age, BW were determined, and 10 poults per treatment were sampled to determine liver (LG) and pectoralis muscle (PC) glycogen content. Poults on IOF treatments A (18% EWP), B (18% EWP + HMB), and D (HMB) weighed 6.0, 2.7, and 3.3% more than the controls at hatch, respectively (P < 0.05) with an EWP x HMB interaction (P < 0.05) sustained to 3 and 7 d only in treatment D (P < 0.005). At hatch, A and D poults had greater percentages of PC (P < 0.05) than controls, and the percentage of PC in treatment D was sustained until 7 d. Total LG was enhanced by A and B at 7 d (P < 0.05) over the controls, whereas total PC glycogen was enhanced at 7 d by IOF treatment D (P < 0.05). The IOF A and S poults had greater BW than the controls at hatch only (P < 0.05). The IOF treatment A had greater LG at hatch (P < 0.05), but by 7 d, A and S had greater LG than controls (P < 0.05). Poults fed S in ovo had enhanced total PC glycogen over controls, whereas poults on treatment A had less total PC glycogen than controls (P < 0.05). The results of this experiment demonstrate that IOF of A or S poults may enhance hatch BW and glycogen status of poults during the neonatal period by inclusion of HMB.

The protective mucus layer covers the entire surface of the gastrointestinal tract. The mucus layer also acts as a medium for molecule transport between the luminal contents and the enterocytes; therefore it has a major role in nutrient absorption. The main mucus layer component, mucin glycoproteins, is produced by mucous-secreting goblet cells. In chicken small intestine, functional development of goblet cells and enterocytes occurs in the late embryonic and immediate posthatch period. Presence of the nutrient is crucial for mucosal development. Feed deprivation immediately after hatch caused delayed mucosa development and perturbed mucin dynamics. Recent studies showed the intraamnionic nutrient supply (in-ovo feeding; IOF) accelerated mucosa functional development. In this study, the effect of IOF on the mucin mRNA expression and mucin content in the goblet cells was studied. The feeding solution containing carbohydrates was administered to the amnionic fluid of the Cobb embryos at d 17.5 of incubation. Samples from the jejunum were taken at d 17 of incubation (before IOF), and then 10 embryos from each group were sampled at 19 d of incubation, at hatch, and at d 3 posthatch. Following IOF, villus surface area increased at day of hatch and 3 d posthatch by 27 and 21%, respectively. In addition, the proportion of goblet cells containing acidic mucin increased 36 h after injection by 50% compared with the controls. The mucin mRNA expression increased gradually from d 17 of incubation to 3 d posthatch. Enhanced expression of the mucin mRNA was found at the day of hatch in chicks that received carbohydrate solution into the amnionic fluid in comparison with the control group. The results showed that providing the carbohydrates as an energy source to the late-term embryo had a trophic effect on the small intestine and enhanced goblet cell development.

This study was to determine apparent ileal digestibility of acid detergent fiber (ADF), neutral detergent fiber (NDF), dry matter (DM), energy, organic matter (OM), crude ash, digesta viscosity, and gut morphology in nursery pigs fed diets containing xylanase (Lohmann Animal Nutrition GmbH, Cuxhaven, Germany). The diet (61% corn, 35% soybean meal, 1% poultry fat, and 3% minerals and vitamins) was mixed with 3 levels of xylanase (0, 700, and 1400 LXU/kg). Thirty-six barrows (17.6 ± 3.3 kg) received one of 3 treatment diets based on a randomized complete block design with the initial body weight (BW) as a block. Pigs were individually housed and received experimental diets twice daily (0700 and 1700 h) at a fixed amount based on BW of pigs (0.09 × BW0.75 kg). Pigs were fed diets for 10 d, and chromium oxide (0.3%) was added to the diets from d 6 as an indigestible external marker. Pigs were euthanized at the end of d 10 for the collection of digesta and tissues. Jejunal digesta were centrifuged to measure viscosity using a viscometer (Brookfield Engineering Laboratories, Stoughton, MA). Diets and freeze-dried ileal digesta were used to measure ADF, NDF, and chromium to calculate apparent ileal digestibility of ADF and NDF. Villus height and crypt depth of jejunum were measured using a microscope (Fisher Scientific, Hampton, NH). Data were analyzed using polynomial contrasts in the MIXED procedure of SAS version 9.3 (SAS Inc., Cary, NC, USA). Morphological measurements and ileal ADF digestibility were not affected by increasing xylanase. However, increasing xylanase supplementation from 0 to 1400 LXU/kg enhanced ileal digestibility of NDF (P < 0.042, linear) from 27.9 to 40.3%, DM (P < 0.006, linear) from 55.4 to 64.6%, OM (P < 0.006, linear) from 59.2 to 67.7%, and energy (P < 0.003, linear) from 58.8 to 68.0%. Viscosity of jejunal digesta decreased (P < 0.023) in a non-linear manner from 2.9 to 2.5 centipoises (cP). In conclusion, the usage of xylanase in corn and soybean meal based pig diets linearly enhanced digestibility of nutrients and affected viscosity of digesta in a non-linear manner.