FISH OIL AND BARLEY SUPPLEMENTATION IN DIETS FOR ADULT DOGS: EFFECTS ON LIPID AND PROTEIN METABOLISM, NUTRIENT DIGESTIBILITY, FECAL QUALITY, AND POSTPRANDIAL GLYCEMIA

Obesity is the most prevalent nutritional disorder encountered in small animal medicine. Problems related with obesity are the higher incidence of morbidity and mortality. Nutritional and physical activity interventions have been common strategies employed; however, they have shown low compliance rates. Because of it more attention has been given to the nutrient composition of diets. Using the canine model, three experiments were conducted to examine the effect of fish oil or barley on protein and lipid metabolism, as well as postprandial glycemia, and nutrient digestibility in mature and in young adult dogs. In Exp. 1, seven female dogs were randomly assigned to one of two isonitrogenous and isocaloric diets, control (CO) or fish oil (FO), in a crossover design. Animals fed the FO diet tended to be more sensitive to glucose, showing a lower glucose half life. Cholesterol and HDL decreased (p\u3c0.05) on the FO treatment. Overall, the supplementation of fish oil may improve glucose clearance rate and is effective in decreasing cholesterol in mature overweight dogs. In Exp. 2, eight female Beagles were randomly assigned to one of two isonitrogenous and isocaloric diets, control (CO) or fish oil (FO), in a crossover design. Overall, feeding a FO containing diet showed a protective effect against the rise of plasma CHOL and it increased plasma ghrelin levels. However, it did not appear to improve protein metabolism or postprandial glycemia in adult lean dogs. In Exp. 3, sixteen female dogs were randomly assigned to four experimental diets; control (40% corn) or three levels of barley (10, 20, 40%). The data suggest that inclusion of barley up to 40% in diets for adult dogs is well tolerated and does not negatively impact nutrient digestibility of the diets. However, inclusion of barley did not improve aspects related to fecal odor, postprandial glycemia, or plasma cholesterol. Overall, the research presented herein suggests that different nutritional strategies - dietary lipid or carbohydrate manipulation - may be beneficial in ameliorating health issues (e.g., hyperlipidemia) or in improving the health status of dogs (e.g., gut health by increased SCFA production)

The effects of sorghum fractions on pet food extrusion, digestibility and antioxidant capacity in dogs

Master of ScienceDepartment of Grain Science and IndustryGreg AldrichNovel ingredients fuel growth in the pet food market. Sorghum grain is a promising ingredient source. It grows in semi-arid regions and the pericarp is rich in phenolic compounds that are well-known antioxidants. The objectives were to determine the impact of milling sorghum on yield and composition of the various fractions, their impact on diet extrusion, and nutrient utilization when fed to dogs. Sorghum milling yields were 68.3% flour, 27.2% mill-feed, and 1.25% germ. Four nutritionally similar dog diets were extruded containing whole sorghum (WSD), sorghum flour (FLD), sorghum mill-feed (MFD), or a control diet (CON) with an equal proportion of corn, wheat and rice. The MFD had the highest (P < 0.05) bulk density and was 1.37-fold heavier than FLD. The FLD had a sectional expansion index (SEI) of 1.92 and 1.35-fold more than MFD and WSD. The FLD and MFD had the hardest kibbles (P < 0.05). Twelve Beagle dogs were fed the experimental diets in a 4 period replicated Latin square design with 9 d adaptation and 5 d total fecal collection (TFC). Fecal output was also estimated using acid insoluble ash (AIA), Cr₂O₃ and TiO₂. Plasma antioxidant activity was measured by oxygen radical absorbance capacity (ORAC) method. Fecal scores were highest (P < 0.05) for MFD treatment and lowest for CON, with FLD and WSD similar to both extremes. Dogs fed the MFD had the largest quantity (P < 0.05) of feces excreted and FLD the least. Dogs fed the FLD had highest (P < 0.05) overall nutrient digestibility values; whereas, MFD had the lowest values. TiO₂ estimates of fecal output correlated best to all other markers. The MFD had more than 2-fold (P < 0.05) the antioxidant value by ORAC versus the other treatments (20,482 vs average 8,923 μM Trolox Equivalent/L). This study suggests that sorghum flour would benefit easy-to-digest foods and the sorghum mill-feed could benefit foods needing indigestible fiber and antioxidants. Titanium dioxide may be a better marker for fecal output than Cr₂O₃ or TFC. Future work should determine the optimal mill-feed level to provide health benefits without affecting nutrient digestibility

Evaluation of alternative sustainable ingredients for use in companion animal diets

Master of ScienceDepartment of Grain Science and IndustryMajor Professor Not ListedThe pet food industry has a unique position in the food system as it largely relies on by- products or co-products from the human food systems for ingredient sourcing. Considering the substantial size of the pet food market, identifying alternative ingredients for use in the pet food industry that are sustainability sourced will be essential. The first objective of this work was to evaluate fermentation characteristics of alternative fiber ingredients using an in vitro canine fecal inoculum model. Organic matter disappearance (OMD) and postbiotic production were determined for apple pomace (AP), blueberry pomace (BP), cranberry pomace (CP), tomato pomace (TP), and pea fiber (PF) incubated with inoculum for 1, 3, 6, and 12 h at 39oC. The OMD was similar (P>0.05; average of 18.5%) between treatments with no effect of time (P>0.05). Total VFA concentration was highest for AP (P0.05) from CM (167 kJ/kg). Kibble sectional expansion and piece volume were greatest for TY (P<0.05). Cats fed TY had greater intake ratios (P<0.05) than CM and PP (0.88 and 0.73, respectively), but were not different (P>0.05) from SM. ATTD of dry matter (DM), organic matter (OM), and gross energy (GE) was greater (P<0.05) for CM (87.43, 91.34, 90.97%, respectively) than TY. The ATTD of DM, OM, and GE was similar (P<0.05) for TY to PP and SM (averages of 86.20, 89.76, and 90.22%, respectively). Crude protein ATTD of TY was similar to other treatments (average of 89.97%), but fat ATTD was lower (P<0.05; 92.52%) than other treatments (93.76 to 94.82%). Total dietary fiber ATTD was similar between TY and CM (average of 66.20%) and greater (P<0.05) than PP and SM (average of 58.70%). In summary, the Torula yeast facilitated kibble formation, increased diet preference, and was highly digestible when fed to cats. The results here provide valuable data on the use of high-fiber food processing by-products and yeast derived proteins in companion animal diets. Alternative ingredients, such as these, have great potential to provide valuable, sustainably sourced ingredients for pet diets

The structure and bioactivity of ulvan, a sulfated polysaccharide from Ulva (chlorophyta)

Joel Kidgell studied ulvan, a unique sulfated polysaccharide from green seaweeds of the genus Ulva. His research detailed how the chemical structure of these molecules is critical in their application as a biomaterial ranging from wound dressings to tissue scaffolds

Investigation of Nutritional and Functional Properties of Resistant Starch in Food Industry: A Review

Abstract -Dietary starches are important sources of energy for many human societies and it is clear that they can also make quite specific contributions to health. Resistant starch (RS) is recently recognized source of fiber and is classified as a fiber component with partial or complete fermentation in the colon, producing various beneficial effects on health. RS also offers an exciting new potential as a food ingredient. Resistant starch (RS) refers to the portion of starch and starch products that resist digestion as they pass through the gastrointestinal tract. The potential physiological benefits of resistant starch, along with its functional properties, provide a means to increase total dietary fiber in the diet through popular foods. Apart from the potential health benefits of resistant starch, another positive advantage is its lower impact on the sensory properties of food compared with traditional sources of fiber, as whole grains, fruits or bran. By formulating foods with resistant starch, product developers and nutritionists can encourage consumers to increase their fiber intake with a variety of palatable, high quality foods that are healthy as well. In this review, we discuss about resistant starch from both its potential health benefits and functional properties in food industry. This research will create a market potential for a range of new health based food to maintain optimal human health

Marine Polysaccharides Volume 1

The field of marine polysaccharides is constantly evolving, due to progress in the discovery and production of new marine polysaccharides. Seaweed remains the most abundant source of polysaccharides, but recent advances in biotechnology have allowed the production of large quantities of polysaccharides from a variety of micro-algae, by controlling growth conditions and tailoring the production of bioactive compounds in a bioreactor. Of particular interest are polysaccharides produced by micro-organisms from extreme marine environments, due to their recognized different biochemistry. Extracellular polysaccharides (EPSs) with unique properties produced by a number of micro-algae are known. The first volume is a collection of papers concerning the identification and characterization of novel marine polysaccharides. It is divided into three chapters; the first two are dedicated to polysaccharides from different marine sources (algae, micro-algae, animals), while the third one gathers information on the isolation, characterization and bioactivity of new EPSs

Molecular understanding of functionality and utilisation of whey protein in novel product concepts with chitosan and starch

The PhD research examines network formation of thermally treated composite biopolymer systems of whey protein isolate (WPI), native wheat starch (WS) and chitosan (CHT). The work builds from the understanding of binary biopolymer systems and moves through investigation of low to intermediate concentrations to bridge the gap in understanding low and high solid tertiary polymer systems. Subsequently, WPI and CHT networks in the presence of gelatinised starch are manipulated and investigated for the potential of reducing the glycemic index at conditions imitating in vivo the human gastrointestinal tract. Aqueous systems consisting of a constant 15% WPI, i.e. over the minimum critical gelling concentration of the protein, and increasing concentrations of up to 15% WS were heated from 25-85°C, followed by cooling from 85-5°C. Following understanding of binary mixtures, various levels of calcium chloride and CHT were incorporated. The experiments conducted include small deformation dynamic oscillation in shear, differential scanning calorimetry (DSC), texture profile analysis, environmental scanning electron microscopy and in vitro starch digestion. The studies on WPI-WS systems argue for the formation of micro phase separated networks that are WPI continuous and WS discontinuous. For example, from the DSC studies endothermic peaks reflecting starch gelatinisation and protein denaturation were resolved and the absence of other events exemplifies associative physicochemical interactions lacking between the two polymers. In the rheological experiments the mixtures exhibited dramatic increases in G’ temperatures more closely related to those observed for individual WPI (73°C) rather than WS (60°C) systems. This pattern prevailed even at high additions of WS (15%), whereby intense G’ values were detected at 70°C. The second set of experiments examined the formation of heat induced WPI and WS gels in the presence of CaCl2 (5-192mM). As followed by rheological experiments, the presence of the salt clearly affected WPI network formation and the influence was concentration dependent. At intermediate levels of incorporation, WPI-WS gels were the least vulnerable to amylolytic attack during digestion experiments. The investigation proves that CaCl2 promotes the aggregation of WPI and incorporation at 48mM provides the optimum spatial structure for maximum reduction in starch degradation. The incorporation of medium molecular weight CHT in WPI-WS preparations at pH 5.5 also exemplifies significant changes on protein aggregation. From the ATR-FTIR work, an increased intensity of the absorbance peak at the amide II region was apparent, with samples containing the heteropolysaccharide, which represents a higher degree of morphological arrangement in the system. Results of the study evidenced electrostatic interactions as the driving force between the CHT and WPI which led to augmentation of infrared spectra. The in vitro starch digestion work on CHT involved comparison between 2% low molecular weight (LMW) and 2% medium molecular weight (MMW) under a digestion model with pH and volume adjustments according to those applicable to the human gastrointestinal tract (mouth, stomach, small intestine). The incorporation of both MMW and LMW CHT assisted in the reduction of starch degradation with the former being of greater effect

Structured emulsion gel systems for delivery of bioactive compounds : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Food Technology at Massey University, Manawatū, New Zealand

Figures are re-used with permission.The structure of solid/semi-solid foods greatly impacts on how the food is broken down and digested in the human body, which affects its sensory perception, and the bioaccessibility of nutrients. In this project, heat-set whey protein emulsion gel was used as a model system for solid/semi-solid foods for the delivery of capsaicinoids (CAP); the capsaicinoids were dissolved in the emulsion droplets. The aim was to investigate the effect of emulsion gel structure on the breakdown properties and sensory perception of the gel in human mouth and to understand how gel structure affects its digestion behaviour as well as the release of capsaicinoids during in vitro gastrointestinal digestion. Small and large deformation properties as well as the microstructure of the emulsion gel were evaluated. Eighteen human subjects were used to investigate in vivo oral processing behaviour and sensory perception. The Human Gastric Simulator (HGS) was used for in vitro dynamic gastric digestion and pH-stat for simulated intestinal digestion. Human intestinal epithelial cells Caco-2 were used to evaluate the irritation effect of gastric digesta by the quantification of human interleukin-8 (IL-8) production using enzyme-linked immunosorbent assay (Elisa). Based on the rheological properties, the gels were classified into three groups: semi-solid gel (whey proteins as emulsifier, 10 mM NaCl with d4,3 of ~ 0.2 µm); soft and elastic gels (whey proteins as emulsifier, 10 mM NaCl with d4,3 of ~ 4, 1 and 0.5 µm); hard and brittle gels (whey proteins as emulsifier, 100 mM NaCl with d4,3 of ~ 4, 1, 0.5 and 0.2 µm). Results from in vivo study indicated that the degree of gel fragmentation during mastication was positively correlated with gel hardness (represented by Young’s modulus). A higher degree of fragmentation led to a greater surface exposure during mastication and, therefore, a greater release of capsaicinoid molecules, resulting in greater mouth burn perception. Results from in vitro gastrointestinal digestion of CAP-loaded soft gel and CAP-loaded hard gel showed that the hard gel was disintegrated and hydrolysed slower than the soft gel during gastric digestion. The rate and extent of lipid digestion during intestinal digestion were affected by several factors, such as fat content, gel structure, gel particle size and initial oil droplet size of the gastric digesta. Generally, the soft gel had higher degree of lipid digestion, mainly because of its soft gel structure and lower fat content. The bioaccessibility of CAP was found to be positively correlated with the extent of lipid digestion. The effect of active (whey proteins as emulsifier) versus inactive (Tween 80 as emulsifier) filler particles of CAP-loaded emulsion gels was also investigated. CAP-loaded Tween-80-coated oil droplets were not bound within the whey protein matrix (i.e. emulsion gels containing inactive filler particles) and appeared to be flocculated and heterogeneously distributed in the gel matrix; this led to drastically decreased gel strength. On the other hand, the whey-protein-coated oil droplets had strong interactions with surrounding whey protein matrix contributing to gel strength, and the oil droplets were relatively evenly distributed in gel matrix in CAP-loaded whey protein emulsion gels (i.e. emulsion gels containing active filler particles). During in vivo oral processing, CAP-loaded Tween 80 emulsion gels were readily broken down into small fragments in the mouth at small deformations with less chewing and released large amounts of oil droplets from the gel matrix. In general, the mouth burn perception was positively correlated with degree of gel fragmentation. The large amounts of oil droplets released from the gel matrix during mastication and the inhomogeneous distribution of the oil droplets of the CAP-loaded Tween 80 emulsion gels also contributed to their greater mouth burn perception. During in vitro gastric digestion, the gel with inactive filler particles was disintegrated and emptied out faster than gel with active filler particles, due to its significantly smaller masticated particle size entering the stomach. Large amounts of oil droplets were released during gastric digestion from the gel with inactive filler particles while gel with active filler particles had minor release of oil droplets at the end of digestion. During intestinal digestion, the presence of Tween 80 in gel with inactive filler particles has slowed down the rate and extent of lipolysis, because Tween 80 had certain resistance against replacement by bile salts from the interface. Moreover, the Tween 80 molecules, once displaced by bile salts from the interface, would also participate in the formation of mixed micelles and help solubilize the released CAP molecules, therefore, leading to improved bioaccessibility of CAP. An in vitro method was developed to quantify the gastric irritation of CAP-loaded food formulations during gastric digestion. Results suggest that Caco-2 cells had immune responses to CAP-loaded samples by secreting significant amounts of IL-8, confirming that CAP molecules are inflammatory to Caco-2 cells. The emulsion gel structure was modified using different emulsifiers: whey proteins versus Tween 80. The gastric digesta from CAP-loaded Tween 80 emulsion gel was able to stimulate more IL-8 production than CAP-loaded whey protein emulsion gel. Tween 80 was found to be a proinflammatory factor to Caco-2 cells and could stimulate IL-8 secretion. Overall, this research provided new information on the use of solid/semi-solid systems for delivery of capsaicinoids and how food structure affects disintegration and digestion behaviour and eventually the release of capsacinoids. The outcomes have potential for designing functional foods containing capsaicinoids, with increased incorporation of capsaicinoids in the foods / pharmaceuticals, reduced irritation in the mouth and stomach and increased bioaccessibility in the intestine

Efforts to capture high amylose in rice

Screening of wild and cultivated rice in IRRI germplasm collection revealed that majority have intermediate apparent amylose content. It appears that ancient farmers selected rice based on texture of the lower amylose varieties, considering that the majority of rice consumers today prefer intermediate to soft-textured rice. Furthermore, 30% seems to be the natural upper natural limit of amylose levels in wild-type rice. If this is the case, the rich biodiversity of rice has been subjected to the bottleneck of domestication to select for grains that have superior cooking and eating but not nutritional or satiating qualities considering that the majority of rice consumers today eat rice three times a day. On the other hand, the amylose content of available rice mutants with deficient SBEIIb or an over-expressed GBSSI also revealed amylose levels of around 35% which is significantly lower by comparison with other high amylose cereals, whose amylose content ranges from 70–90%. Hence, to produce the high amylose phenotype in rice, one might need to target different sets of enzymes or regulatory pathways. Since increasing the amylose levels in rice might mean a concomitant increase in its resistant starch content and in its levels of satiety, and a decrease in its glycemic response, developing high amylose rice by biotechnology is imperative. This type of rice will be important not only in addressing the growing obesity epidemic which now also affects the developing countries but also as a basis of novel degradable biopolymers and for further elucidating the mechanisms of starch synthesis in the cereal endosperm. In this paper, we also present the status of our research project which aims to silence the expression of SBEIIa, SBEIIb and SSIIa singly or in combination using microRNA and RNAi silencing technologies with the aim of increasing the amylose levels in rice beyond its natural limits