Guar meal germ and hull fractions differently affect growth performance and intestinal viscosity of broiler chickens

Substitution of fishmeal: Highlights of potential plant protein sources for aquaculture sustainability

High protein content, excellent amino acid profile, absence of anti-nutritional factors (ANFs), high digestibility and good palatability of fishmeal (FM), make it a major source of protein in aquaculture. Naturally derived FM is at risk due to an increase in its demand, unsustainable practices, and price. Thus, there is an urgent need to find affordable and suitable protein sources to replace FM. Plant protein sources are suitable due to their widespread availability and low cost. However, they contained certain ANFs, deficiency of some amino acids, low nutrient bioavailability and poor digestibility due to presence of starch and fiber. These unfavourable characteristics make them less suitable for feed as compared to FM. Thus, these potential challenges and limitations associated with various plant proteins have to be overcome by using different methods, i.e. enzymatic pretreatments, solvent extraction, heat treatments and fermentation, that are discussed briefly in this review. This review assessed the impacts of plant products on growth performance, body composition, flesh quality, changes in metabolic activities and immune response of fishes. To minimize the negative effects and to enhance nutritional value of plant products, beneficial functional additives such as citric acid, phytase and probiotics could be incorporated into the plant-based FM. Interestingly, these additives improve growth of fishes by increasing digestibility and nutrient utilization of plant based feeds. Overall, this review demonstrated that the substitution of fishmeal by plant protein sources is a plausible, technically-viable and practical option for sustainable aquaculture feed production.

Guar gum as galactomannan source induces dysbiosis and reduces performance in broiler chickens and dietary β-mannanase restores the gut homeostasis

Galactomannans are abundant nonstarch polysaccharides in broiler feed ingredients. In broilers, diets with high levels of galactomannans have been associated with innate immune response stimulation, poor zootechnical performance, nutrient and lipid absorption, and excessive digesta viscosity. However, data about its effects on the gut microbiome are scarce. β-Mannanases are enzymes that can hydrolyze β-mannans, resulting in better nutrient utilization. In the current study, we have evaluated the effect of guar gum, a source of galactomannans, supplemented to broiler diets, either with or without β-mannanase supplementation, on the microbiota composition, in an attempt to describe the potential role of the intestinal microbiota in β-mannanase-induced gut health and performance improvements. One-day-old broiler chickens (n = 756) were randomly divided into 3 treatments: control diet, guar gum-supplemented diet (1.7%), or guar gum-supplemented diet + β-mannanase (Hemicell 330 g/ton). The zootechnical performance, gut morphometry, ileal and cecal microbiome, and short-chain fatty acid concentrations were evaluated at different time points. The guar gum supplementation decreased the zootechnical performance, and the β-mannanase supplementation restored performance to control levels. The mannan-rich diet-induced dysbiosis, with marked effects on the cecal microbiota composition. The guar gum-supplemented diet increased the cecal abundance of the genera Lactobacillus, Roseburia, Clostridium sensu stricto 1, and Escherichia-Shigella, and decreased Intestinimonas, Alistipes, Butyricicoccus, and Faecalibacterium. In general, dietary β-mannanase supplementation restored the main microbial shifts induced by guar gum to levels of the control group. In addition, the β-mannanase supplementation reduced cecal isobutyric, isovaleric, valeric acid, and branched-chain fatty acid concentrations as compared to the guar gum-supplemented diet group, suggesting improved protein digestion and reduced cecal protein fermentation. In conclusion, a galactomannan-rich diet impairs zootechnical performance in broilers and results in a diet-induced dysbiosis. β-Mannanase supplementation restored the gut microbiota composition and zootechnical performance to control levels.

Guar gum-derived galactomannan induces inflammatory responses and increased energy expenditure in the intestine

Guar gum-derived galactomannan (GGGM) has been widely used in the food industry for a long time and its adverse impacts have been scarcely reported. Galactomannan is considered to have a structure similar to the surface components of certain pathogens, and the present study was thus conducted to investigate if oral administration of GGGM could cause physiological effects that were hypothesized to be related to intestinal inflammatory responses. The results showed that oral administration of GGGM resulted in compromises on growth performance, an increase of the relative weight of spleen and epididymal fat, and an elevation of the α1-acid glycoprotein content in both serum and livers of mice. With regard to energy metabolism-related indices, the activities of intestinal lactic dehydrogenase and succinic dehydrogenase were all increased by the GGGM treatment in both in vivo and in vitro experiments, the latter of which also showed an elevation in the consumption of reducing sugar by intestinal epithelial cells along with a reduced viability of these cells in response to the GGGM treatment. Notably, the GGGM treatment triggered intestinal inflammatory responses that were evidenced by the increased expression of intestinal inflammatory cytokines such as TNF-α and IL-6 both in vivo and in vitro, which were at least partially responsible for the increased energy expenditure in the intestine and the retardation of growth. The results of this study could expand our knowledge of GGGM administration and provide integrated insights into the consumption of GGGM-containing foods.

Physiological parameter values for physiologically based pharmacokinetic models in food-producing animals. Part II: Chicken and turkey

Physiologically based pharmacokinetic (PBPK) models are growing in popularity due to human food safety concerns and for estimating drug residue distribution and estimating withdrawal intervals for veterinary products originating from livestock species. This paper focuses on the physiological and anatomical data, including cardiac output, organ weight, and blood flow values, needed for PBPK modeling applications for avian species commonly consumed in the poultry market. Experimental and field studies from 1940 to 2019 for broiler chickens (1-70 days old, 40 g - 3.2 kg), laying hens (4-15 months old, 1.1-2.0 kg), and turkeys (1 day-14 months old, 60 g -12.7 kg) were searched systematically using PubMed, Google Scholar, ProQuest, and ScienceDirect for data collection in 2019 and 2020. Relevant data were extracted from the literature with mean and standard deviation (SD) being calculated and compiled in tables of relative organ weights (% of body weight) and relative blood flows (% of cardiac output). Trends of organ or tissue weight growth during different life stages were calculated when sufficient data were available. These compiled data sets facilitate future PBPK model development and applications, especially in estimating chemical residue concentrations in edible tissues to calculate food safety withdrawal intervals for poultry.

Effects of dietary inclusion of GuarPro F-71 on the growth performance and nutrient metabolism in young growing pigs

Using alternative feedstuffs can be a feasible measure to reduce swine production cost. GuarPro F-71 (GP71), a newly developed guar meal product, is considered as a potential protein source for pigs. This preliminary study was conducted to evaluate the effects of GP71 inclusion in feed on growth performance and nutrient metabolism of growing pigs. Sixty crossbred barrows (31.9±1.84 kg body weight (BW)) were allotted to one of five dietary treatments in a completely randomised experiment design, with four pens/treatment and three pigs/pen. Diet 1 was a maize- and soybean-based basal control diet formulated to meet NRC recommendations. GP71 was used to replace 25, 50, 75, and 100% soybean meal in diet 1 (on an equivalent crude protein (CP) basis) to generate diets 2, 3, 4, and 5, respectively. Crystalline amino acids were used to balance the essential amino acid concentrations across the five diets. Inclusion of GP71 quadratically reduced average daily feed intake (ADFI) (P=0.01) with no observed clinical signs of unhealthiness of pigs. The blood plasma concentrations of six metabolites, including urea nitrogen, total protein, albumin, glucose, total cholesterol and total triglycerides, were not affected (P>0.30), indicating that the pigs’ metabolic utilisation of nutrients was not compromised. The cubic effect (P<0.05) of dietary GP71 inclusion on G:F ratio suggested that the level of soybean meal replacement (up to 75% soybean meal) did not negatively affect feed efficiency in pigs. In short, the feed intake reduction due to the dietary GP71 inclusion was, if not solely, responsible for the average daily gain (ADG) and final BW reduction. This study suggested that using GP71 to replace soybean meal up to 75% (on an equivalent CP basis) can negatively affect ADFI and ADG, but not feed efficiency, in growing pigs. The reasons for the ADFI and ADG reduction need to be understood in future research.

Effect of commercial guar meal (CGM) on the performance and nutrient utilization in broilers

A biological trial was undertaken to study the effect of inclusion of graded levels of commercial guar meal (CGM) in diet on the performance and nutrient digestibility in commercial broiler chickens. A total of 350 oneday- old broiler male chicks (Cobb 400) were reared on wire floor electrically heated battery brooders. The chicks were randomly divided into 7 groups. Each treatment had 10 replicates of 5 chicks each. All the groups received iso-nitrogenous and iso-caloric diets. First group was fed maize-SBM; 2nd, 3rd and 4th groups were fed control diet during pre-starter phase (1–14 days), later (starter and finisher phase) CGM was incorporated at 6, 12 and 18% respectively, replacing SBM. In rest 3 groups (5th, 6th and 7th), CGM was incorporated at 6% during pre-starter phase followed by (starter and finisher phase) incorporation of CGM at 6, 12 and 18% respectively. The results showed that body weight gain (BWG) was significantly better at 6% CGM inclusion and depressed at 12 and 18% CGM. There was no significant effect of non-inclusion of CGM in juvenile phase on BWG; though feed intake did not differ significantly by CGM inclusion but FCR was significantly higher at all inclusion levels of CGM (6, 12 and 18%). The slaughter parameters, nutrient digestibility, serum parameters did not differ significantly. It can be concluded that CGM could be incorporated up to 6% (60 g/kg diet) in broiler diets without affecting growth performance, nutrient utilization and slaughter variables.

Effect of incremental levels of dietary total sulfur amino acids on performance of white leghorn laying hens fed diets containing guar (Cyamopsis tetragonoloba) meal

BACKGROUND

The present study evaluated the potential of increasing dietary levels of the most limiting amino acids such as total sulfur amino acids (TSAA) with respect to mitigating the adverse effects of the inclusion of guar meal (GM) in the diet of WL layers on egg production, feed efficiency and egg weight. In total, 4928 WL (Lohmann L) hens (32 week of age) were randomly allotted to eight treatments with seven replicates of 88 birds. The dietary treatments were a set of four maize-soybean meal based diets containing four graded concentrations of TSAA (5.85, 6.18, 6.51 and 6.84 g kg^-1 ) and another set of four diets containing 100 g kg^-1 guar meal (GM) with similar concentrations of TSAA.

RESULTS

The inclusion of 100 g kg^-1 GM in the diet caused a 20%, 23%, 35.5% and 6.7% reduction in egg production, daily egg mass, feed efficiency and egg weight, respectively, when the diet contained 5.85 g kg^-1 TSAA. Increasing TSAA levels in GM groups reduced the adverse effects on egg production and feed efficiency 50%, with no effect on egg weight. The TSAA requirement of WL birds fed 10% GM was estimated as 6.28-7.39 g kg^-1 diet at different ages.

CONCLUSION

Increasing dietary TSAA to 7.39, 6.28, 6.53 and 6.37 g kg^-1 or dTSAA (digestible TSAA) to 6.53, 5.32, 5.80 and 5.63 g kg^-1 during 33-36, 37-40, 41-44 and 45-48 weeks of age, respectively, may be an effective and practical strategy for reducing the adverse effects of inclusion of 100 g kg^-1 GM in the diet of WL layers. © 2018 Society of Chemical Industry.

Efficacy of β-mannanase on broiler growth performance and energy utilization in the presence of increasing dietary galactomannan

An experiment was conducted to investigate the impact of β-mannanase inclusion on growth performance, viscosity, and energy utilization in broilers fed diets varying in galactomannan (GM) concentrations. Treatments were arranged as a 3 (GM concentration) × 3 (β-mannanase inclusion) factorial randomized complete block design with 12 replicates of 29 male broilers per replicate for a 42-d experiment. Efforts were made to reduce the amount of soybean meal, and thus GM, in the basal diet with guar gum included at 0, 0.21, or 0.42% to achieve a GM supplementation of 1,500 and 3,000 ppm, respectively. Beta-mannanase was included at 0, 200, or 400 g/ton. Broilers were fed a starter (d 0 to 14), grower (d 15 to 28), and finisher diets (d 29 to 42). Growth performance was monitored and ileal contents collected on d 14, 28, and 42 to determine ileal digestible energy (IDE) and intestinal viscosity. Increasing levels of GM negatively (P < 0.05) influenced body weight (BW) following the starter and grower periods and increased (P < 0.01) mortality corrected feed conversion ratio (FCR) throughout the study. Reduced growth performance was associated with increased (P < 0.05) intestinal viscosity and decreased (P < 0.05) IDE when GM inclusion was increased. Inclusion of β-mannanase in diets containing supplemental GM on d 28, increased average BW to levels similar to diets without supplemental GM. Improvements in FCR were also observed with β-mannanase inclusion in diets containing supplemental GM. Ileal digestible energy was increased (P < 0.05) with the addition of β-mannanase on d 28 of age. Multiple interactions in growth performance, intestinal viscosity, and IDE were associated with β-mannanase administration. In conclusion, β-mannanase improved IDE, reduced intestinal viscosity, and improved growth performance; however, the observed benefit was dependent upon dietary GM concentration.

Estimation of the maximum safe level of feed ingredients by spline or broken-line nonlinear regression models

The use of non-linear regression models in the analysis of biological data has led to advances in poultry nutrition. Spline or broken-line nonlinear regression models are commonly used to estimate nutritional requirements. One particular application of broken-line models is estimating the maximum safe level (MSL) of feed ingredients beyond which the ingredients become toxic, resulting in reduced performance. The objectives of this study were to evaluate the effectiveness of broken-line models (broken-line linear or BLL; and broken-line quadratic or BLQ) in estimating the MSL; to identify the most efficient design of feeding trials by finding the optimal number of ingredient levels and replications; and to re-estimate the MSL of various test ingredients reported in the nutrition literature for comparison purposes. The Maximum Ingredient level Optimization Workbook (MIOW) was developed to simulate a series of experiments and estimate the MSL and the corresponding descriptive statistics (SD, SE, CI, and R2). The results showed that the broken-line models provided good estimates of the MSL (small SE and high R2) with the BLL model producing higher MSL values as compared to the BLQ model. Increasing the number of experimental replications or ingredient levels (independently of each other) reduced the SE of the MSL with diminishing returns. The SE of the MSL was reduced with increasing the size (total pens) of the simulated experiments by increasing either the number of replications or levels or both. The evaluation of MSLs reported in the existing literature revealed that the multiple range procedure used to determine the MSL in several reports can both overestimate and underestimate the MSL compared to the results obtained by the broken-line models. The results suggest that the broken-line linear models can be used in lieu of the multiple range test to estimate the MSL of feed ingredients along with the corresponding descriptive statistics, such as the SE of the MSL.

β-Mannanase Derived from Bacillus Subtilis WL-7 Improves the Performance of Commercial Laying Hens Fed Low or High Mannan-Based Diets

A trial was conducted to investigate the effects of dietary mannan level and β-mannanase supplementation on egg production performance, nutrient retention and blood metabolites of laying hens. Two hundred and forty Hy-Line Brown layers (52 wk-old) were randomly allotted to 6 treatments on the basis of laying performance. Each treatment had 8 replicates with 5 birds (40 birds per treatment). Laying hens were fed low or high mannan diets containing 0, 0.4 or 0.8 g β-mannanase/kg diet in a 2×3 factorial arrangement during 56 d feeding period. Laying hens fed diets supplemented with high β-mannanase level had greater (P<0.05) overall egg production, egg weight, egg mass, retention of gross energy, crude protein and mannan than hens fed the diets without β-mannanase. Laying hens fed diets without β-mannanase or supplemented with high β-mannanase level had greater (P<0.05) retention of dry matter than hens fed diets with low β-mannanase level. Moreover, laying hens fed high mannan diets had higher (P<0.05) feed intake and feed conversion ratio than that of hens fed low mannan diets. Furthermore, laying hens fed diets supplemented with a high level of β-mannanase had increased serum glucose (P<0.05) concentrations but these diets had no effect on total cholesterol, total protein or blood urea nitrogen. The results obtained in the present study indicate that a high mannan content in diets had adverse effect on the performance of laying hens and that dietary supplementation with β-mannanase has the potential to improve laying hen performance and nutrient retention.

Growth performance of broilers fed on sprouted-roasted guar bean (Cyamopsis tetragonoloba) based diets

In a completely randomized block design with 96 Cobb-500 broilers, a study was conducted to evaluate the potential of dietary inclusion of sprouted then roasted guar bean in broiler diets. The 96 male day-old broiler chicks, blocked by pen into equal weight groups of six chicks replicated four times per treatment, were randomly allocated to treatment diets containing graded levels of sprouted then roasted guar bean meal (GBM) at 0, 50, 100 and 150 g kg^-1 inclusion level. The guar bean was sprouted and roasted to reduce guar gum effect. Total feed intake decreased significantly as the guar bean meal content increased in the starter phase (P < 0.05), but no significant differences in intake of the finisher phase (P > 0.05) were observed. Diets containing 0 and 50 g kg^-1 GBM recorded significantly higher total feed intake compared to the diet containing 150 g kg^-1 GBM. Although average weight gain was not significantly different in birds fed 0 and 50 g kg^-1 GBM diets, it was significantly higher than in birds fed on 100 and 150 g kg^-1 GBM diets. Feed conversion ratio was not significantly different among treatment groups (P > 0.05) but showed a general decreasing trend with increasing guar bean meal inclusion level, the effect being more pronounced during the starter phase. In conclusion, the optimum inclusion level of sprouted then roasted guar bean meal in broiler diets is 50 g kg^-1.

Alternative Protein Sources in the Diet Modulate Microbiota and Functionality in the Distal Intestine of Atlantic Salmon (Salmo salar)

The present study aimed to investigate whether alternative dietary protein sources modulate the microbial communities in the distal intestine (DI) of Atlantic salmon, and whether alterations in microbiota profiles are reflected in modifications in host intestinal function and health status. A 48-day feeding trial was conducted, in which groups of fish received one of five diets: a reference diet in which fishmeal (diet FM) was the only protein source and four experimental diets with commercially relevant compositions containing alternative ingredients as partial replacements of fishmeal, i.e., poultry meal (diet PM), a mix of soybean meal and wheat gluten (diet SBMWG), a mix of soy protein concentrate and poultry meal (diet SPCPM), and guar meal and wheat gluten (diet GMWG). Samples were taken of DI digesta and mucosa for microbial profiling using high-throughput sequencing and from DI whole tissue for immunohistochemistry and expression profiling of marker genes for gut health. Regardless of diet, there were significant differences between the microbial populations in the digesta and the mucosa in the salmon DI. Microbial richness was higher in the digesta than the mucosa. The digesta-associated bacterial communities were more affected by the diet than the mucosa-associated microbiota. Interestingly, both legume-based diets (SBMWG and GMWG) presented high relative abundance of lactic acid bacteria in addition to alteration in the expression of a salmon gene related to cell proliferation (pcna). It was, however, not possible to ascertain the cause-effect relationship between changes in bacterial communities and the host's intestinal responses to the diets.IMPORTANCE The intestine of cultivated Atlantic salmon shows symptoms of compromised function, which are most likely caused by imbalances related to the use of new feed ingredients. Intestinal microbiota profiling may become in the future a valuable endpoint measurement in order to assess fish intestinal health status and effects of diet. The present study aimed to gain information about whether alternative dietary protein sources modulate the microbial communities in the Atlantic salmon intestine and whether alterations in microbiota profiles are reflected in alterations in host intestinal function and health status. We demonstrate here that there are substantial differences between the intestinal digesta and mucosa in the presence and abundance of bacteria. The digesta-associated microbiota showed clear dependence on the diet composition, whereas mucosa-associated microbiota appeared to be less affected by diet composition. Most important, the study identified bacterial groups associated with diet-induced gut dysfunction that may be utilized as microbial markers of gut health status in fish.

Effect of dietary inclusion of toasted guar (Cyamopsis tetragonoloba) meal as a source of protein on performance of White Leghorn layers

Two experiments were conducted to study the effect of including toasted (120°C/35 min) guar meal (GM, Cyamopsis tetragonoloba) in the diet on performance and egg shell quality of White Leghorn (WL) layers. Totals of 2376 and 2816 layer chickens (Babcock, BV 300) were randomly distributed into 27 and 32 replicates with 88 birds each in Experiments 1 and 2, respectively. Three diets in Experiment 1 (0, 50 and 100 g GM) and 4 diets in Experiment 2 (0, 50, 100 and 150 g GM/kg) were prepared having similar concentrations of energy and protein. Each diet was fed ad libitum to 9 and 8 replicates, respectively, in Experiments 1 (from 53 to 68 weeks) and 2 (35 to 46 weeks of age). Compared to soya bean meal (SBM) GM contained similar concentrations of protein, but was deficient in all essential amino acids except arginine, which was 70% higher than in SBM. Total non-starch polysaccharide (NSP) content in GM (166 g/kg) was lower than that of SBM (179 g/kg). Amongst different NSP fractions, GM contained higher levels of arabans, xylans, mannans and glucans compared to SBM. The galactomannan gum content in GM was 46 g/kg. Egg production (EP), body weight (BW), food intake (FI), food efficiency (FE) and egg quality (shell weight, shell per cent, shell thickness, Haugh unit score, egg density and egg breaking strength) parameters were not affected by incorporating GM up to 100 g/kg diet in Experiment 1. However, egg weight (EW) and egg mass (EM) were reduced significantly in groups fed on 100 g/kg diet. In Experiment 2, EP and FE were not affected by incorporating GM up to 100 g/kg, but were reduced at 150 g/kg diet. FI, EW, BW and egg quality parameters were not affected by incorporating toasted GM up to 150 g/kg diet. Based on the results of both experiments, it is concluded that toasted GM can be included in WL layer diets up to 100 g/kg without affecting EP, FE, EW, EM, Haugh unit score, BW and egg shell quality parameters.

Effects of feeding distillers dried grains with solubles to broilers from 0 to 28 days posthatch on broiler performance, feed manufacturing efficiency, and selected intestinal characteristics

This study evaluated the effect of 2 levels (0 vs. 8%) of distillers dried grains with solubles (DDGS) in a starter broiler diet (0 to 14 d; 45 replicates/treatment) after these same birds were subsequently fed a grower diet (14 to 28 d) with either 0, 7.5, 15, 22.5, or 30% DDGS (9 replicates/treatment). Ross×Ross 308 male broilers were used in this experiment, and evaluation criteria consisted of feed mill parameters, broiler growth, relative liver weight, ileal viscosity, and cecal content count of Clostridium perfringens and Escherichia coli analyzed by both selective media and real-time PCR. Increased inclusion of DDGS resulted in a nonlinear response for production rate (P<0.05), conditioner energy usage (P<0.01), and pellet mill energy usage (P<0.05). Increasing DDGS resulted in a linear decrease in pellet quality (P<0.001) and an increase (P<0.001) in total fines. Inclusion of DDGS decreased (P<0.001) energy usage at the pellet mill and decreased (P<0.05) bulk density of the diets. The DDGS levels fed during the starter phase (0 vs. 8%) had no effect on the broilers at 14 or at 28 d of age. Increasing DDGS inclusion levels during the grower phase resulted in a linear decrease (P<0.001) in BW gain and liver relative weight (P<0.001). A DDGS starter×grower interaction (P<0.05) was observed for feed consumption, in which birds that consumed no DDGS during the starter phase exhibited a decrease in feed consumption with the higher inclusion levels of DDGS during the grower phase, whereas birds that received 8% DDGS during the starter phase were unaffected by DDGS inclusion level in the grower phase. Feed conversion, mortality, ileal viscosity, and cecal C. perfringens and E. coli concentrations were unaffected by DDGS level in the grower diet. The feed intake response suggests a beneficial effect of exposing broiler chicks to DDGS if inclusion levels of 22.5% or higher are to be fed after 14 d of age. However, the data suggest that the young broiler can be negatively affected with inclusion levels of 15% DDGS or higher up to 28 d of age.

Guar meal ameliorates Eimeria tenella infection in broiler chicks

Guar meal contains relatively high levels of saponins, which are known to have antiprotozoal activity and may be effective against coccidiosis. A 2x2 factorial experiment investigated the impact of guar meal (0 or 5%) corn-soy-based starter broiler diets on chicks unchallenged or challenged with Eimeria tenella. At 1 day of age, 120 unsexed RossxRoss broiler chicks were randomly distributed among four treatment groups. Chicks were challenged with 5x10(3) sporulated oocysts of E. tenella in 0.5 ml at 10 days of age by oral gavage. Weekly body weight, body weight gains, feed conversion ratio and mortality rate were recorded for chicks fed from 0 to 21 days of age. Oocysts shed per gram feces were recorded from 6 to 10 days post-challenge. Results showed that challenged chicks fed 0% guar meal had significantly higher oocysts per gram shed in feces than the other groups. No significant differences among treatment groups in mortality rate were observed. Body weights of unchallenged and challenged chicks fed 0% guar meal were significantly higher than those fed 5% guar meal at 2 weeks of age. Results indicated that including 5% guar meal in the diet of chicks challenged with E. tenella decreased oocysts shed per gram feces and prevented bloody diarrhea, but without affects on body weight and feed conversion ratio at 11 days post-challenge.

Use of guar by-products in high-production laying hen diets

A 5x5 Latin square experiment was conducted to evaluate the effect of feeding low concentrations of guar germ or a combination of guar germ and hull (guar meal) in high-production laying hen diets. A total of 125 Lohmann laying hens (21 wk old) of similar BW were randomly assigned to 5 blocks. Each block was divided into 5 experimental units, consisting of 5 hens per unit. Hens were fed either a nonguar control diet, or 1 of 4 diets containing either 2.5 or 5% guar germ, or 2.5 or 5% guar meal over a 20-wk trial period (five 4-wk periods). No significant differences were observed when feeding either 2.5 or 5% guar germ or meal (P>0.05) on hen-day egg production or feed consumption. Significant differences in egg weight, total egg mass per hen, and feed conversion ratio were detected in hens fed 2.5% guar meal, whereas they remained unchanged for diets containing either level of guar germ or 5% guar meal. Feeding either level of guar germ or guar meal did not affect shell quality (shell thickness, egg breaking force, and specific gravity), Haugh units, or egg yolk color (L*, a*, b*). The results showed that both guar germ and guar meal can be fed to high-production laying hens at up to 5% without adverse effects on laying hen performance.

Food intake and ingredient profile affect viscosity of ileal digesta of dogs

Two experiments were conducted to determine dietary factors affecting digesta viscosity. In experiment 1, six ileal-cannulated dogs were either full (607.1 kJ/BW0.67) or restricted (303.5 kJ/BW0.67) fed. In experiment 2, four dog foods were surveyed for effects on digesta viscosity based on protein source [animal protein (AP) or plant protein (PP)] or dietary fibre source [soluble dietary fibre (SDF) or insoluble dietary fibre (IDF)]. Dry matter (DM) intake was higher (p<0.05) when dogs were full (11.4 g/kg) compared with restricted fed (5.98 g/kg). Ileal digesta viscosity tended to be higher (p=0.07) for full fed [10,251 centipoise (cP)] compared with restricted-fed dogs (6677 cP). Ileal digesta viscosities were 6561, 11,074, 13,830 and 15,967 cP for dogs consuming IDF, SDF, AP and PP treatments respectively. Ileal DM concentrations were 11.4%, 13.6%, 14.8% and 14.8% for SDF, IDF, AP and PP treatments respectively. DM digestibility coefficients were lowest (71.2%) for the PP treatment and highest (88.7%) for the IDF treatment. Organic matter digestibilities followed a similar pattern. Ileal digesta viscosity of dogs appears to increase with increased diet intake, and increased ileal DM concentration. More digestible diets result in less ileal DM and lower viscosity constants.

Diet type affects viscosity of ileal digesta of dogs and simulated gastric and small intestinal digesta

Two experiments were conducted to determine effects of diet type on viscosity of ileal digesta of dogs and simulated gastric and small intestinal digesta. In experiment 1, three canned and three dry dog foods were surveyed for effects on ileal digesta viscosity. Experiment 2 evaluated the same six diets for effects on simulated gastric and small intestinal digesta. Canned diets and dry diets contained an average 22.7% and 89.9% dry matter (DM) respectively. Concentrations of total dietary fibre (TDF) in the diets ranged from 1.8% to 26.5%. Ileal digesta viscosities ranged from 1326 to 46,641 and 7748 to 10,208 cP for canned and dry treatments respectively. Ileal DM concentrations ranged from 8.2% to 16.2% and 15.4% to 15.8% for canned and dry treatments respectively. Dry matter intake ranged from 224 to 290 and 295 to 325 g/day for canned and dry treatments respectively. During gastric digestion simulation, viscosity peaked at 2 and 4 h for all three canned diets and dry diets respectively. During small intestinal digestion simulation, viscosity peaked between 6 and 12 h for most diets except one canned diet and one dry diet, which contained high concentrations of TDF (25.1% and 26.5% respectively). Viscosity of these solutions peaked between 12 and 18 h. Viscosity of ileal digesta and simulated gastric and small intestinal digesta was the lowest after consumption of canned diets with the exception of the canned diet containing very high concentrations of dietary fibre (25.1% TDF). Ileal digesta viscosity of dogs appears to be responsive to the diet type characteristics.

Viscosity as Related to Dietary Fiber: A Review

Viscosity is a physicochemical property associated with dietary fibers, particularly soluble dietary fibers. Viscous dietary fibers thicken when mixed with fluids and include polysaccharides such as gums, pectins, psyllium, and beta-glucans. Although insoluble fiber particles may affect viscosity measurement, viscosity is not an issue regards insoluble dietary fibers. Viscous fibers have been credited for beneficial physiological responses in human, animal, and animal-alternative in vitro models. The following article provides a review of viscosity as related to dietary fiber including definitions and instrumentation, factors affecting viscosity of solutions, and effects of viscous polysaccharides on glycemic response, blood lipid attenuation, intestinal enzymatic activity, digestibility, and laxation.

Effects of guar meal by-product with and without beta-mannanase Hemicell on broiler performance

Guar gum production yields a high protein guar meal that can be subdivided into germ and hull fractions. Feeding high concentrations of guar meal reduces body weight and feed efficiency in chickens due to the presence of a residual guar gum. Two experiments determined the upper feeding levels of guar meal and the hull and germ fractions in broiler chickens. An industrial source beta-mannanase (Hemicell) also was fed in combination with guar meals. Experiment 1 utilized a 3 x 4 factorial design to feed broiler chickens diets containing guar germ, guar hull, or guar meal at 4 levels (2.5, 5.0, 7.5, and 10.0%) compared with a negative control diet. Results indicated that any of the 3 guar meals could be fed at a 2.5% dietary inclusion rate without adversely affecting broiler chicken growth to 6 wk of age. In experiment 2, a 4 x 2 factorial design consisting of the 3 by-products meals at 5% inclusion and soybean meal control with and without enzyme tested whether Hemicell could increase inclusion rates without decreasing broiler growth or feed consumption to 6 wk of age. Addition of Hemicell to feed had no effect on measures of growth in chickens fed the control diet. Hemicell significantly improved feed:gain ratio of diets containing 5% of each fraction of guar meal versus the untreated diets. Feed:gain ratio for the Hemicell-treated 5% germ fraction diet was improved to control diet levels. Results indicated that the upper feeding level of guar meal and germ and hull fraction of guar meal is 2.5%, and addition of beta-mannanase (Hemicell) increases the upper feeding level for the germ fraction to 5%.