Comparison of procedures for assessing adequacy of dog foods.

Dog foods with similar claims for nutritional adequacy were tested by chemical analysis and the American Association of Feed Control Officials' growth trial. All foods tested were similar chemically, however, dogs given one regionally marketed food had lower growth rate and food efficiency as well as suboptimal PCV and hemoglobin values during the growth trial. Pups fed this diet also had clinical signs typical of zinc and copper deficiencies. We concluded that American Association of Feed Control Officials' approved feeding tests provide valid assessment of pet food quality, and procedures involving only chemical analysis or calculated values may not.     

Understanding regulations affecting pet foods

In the United States, pet foods are subject to regulation at both the federal and the state levels. The US Food and Drug Administration has jurisdiction over all animal feeds (including pet foods, treats, chews, supplements, and ingredients) in interstate commerce, which includes imported products. Many states adopt and enforce at least in part the Association of American Feed Control Officials Model Bill and Model Regulations for Pet Food and Specialty Pet Food. Thus, all pet foods in multi-state distribution are subject to a host of labeling requirements covering aspects such as product names, ingredient lists, nutrient content guarantees, and nutritional adequacy statements. Ingredients must be GRAS (generally recognized as safe) substances, approved food additives, or defined by Association of American Feed Control Officials for their intended use. Pet food labels may not bear claims that are false or misleading or that state or imply use for the treatment or prevention of disease. Pet foods that are found to be adulterated or misbranded may be subject to seizure or other enforcement actions.     

Effects of dietary fat and L-carnitine on plasma and whole blood taurine concentrations and cardiac function in healthy dogs fed protein-restricted diets

OBJECTIVE: To evaluate plasma taurine concentrations (PTC), whole blood taurine concentrations (WBTC), and echocardiographic findings in dogs fed 1 of 3 protein-restricted diets that varied in fat and L-carnitine content. ANIMALS: 17 healthy Beagles. DESIGN: Baseline PTC and WBTC were determined, and echocardiography was performed in all dogs consuming a maintenance diet. Dogs were then fed 1 of 3 protein-restricted diets for 48 months: a low-fat (LF) diet, a high-fat and L-carnitine supplemented (HF + C) diet, or a high-fat (HF) diet. All diets contained methionine and cystine concentrations at or above recommended Association of American Feed Control Officials (AAFCO) minimum requirements. Echocardiographic findings, PTC, and WBTC were evaluated every 6 months. RESULTS: The PTC and WBTC were not significantly different among the 3 groups after 12 months. All groups had significant decreases in WBTC from baseline concentrations, and the HF group also had a significant decrease in PTC. One dog with PT and WBT deficiency developed dilated cardiomyopathy (DCM). Taurine supplementation resulted in significant improvement in cardiac function. Another dog with decreased WBTC developed changes compatible with early DCM. CONCLUSIONS AND CLINICAL RELEVANCE: Results revealed that dogs fed protein-restricted diets can develop decreased taurine concentrations; therefore, protein-restricted diets should be supplemented with taurine. Dietary methionine and cystine concentrations at or above AAFCO recommended minimum requirements did not prevent decreased taurine concentrations. The possibility exists that AAFCO recommended minimum requirements are not adequate for dogs consuming protein-restricted diets. Our results also revealed that, similar to cats, dogs can develop DCM secondary to taurine deficiency, and taurine supplementation can result in substantial improvement in cardiac function.     

Equations used to develop commercial dog food feeding guidelines and Canadian owner feeding practices in 2018

Feeding guidelines on commercial dog food packages provide a suggested starting point for food provision for dogs. The equations used to develop commercial dog food feeding guidelines and the owner feeding practices surveyed were examined in this study. The equations used to develop feeding guidelines and the energy density calculation method (Traditional Atwater or Modified Atwater equation) were investigated for 200 dry dog foods sold in Canada. Not all energy densities of products were calculated using the modified Atwater equation, a requirement if claiming compliance with the Association of American Feed Control Officials (AAFCO). Commercial feeding guidelines provide conservative estimates of pet dog energy needs. A survey of dog owners’ feeding practices was conducted, with 739 responses analyzed. Respondents generally took appropriate action to manage the weight of their dogs through both exercise and dietary management. Further investigation should explore how owners may be successfully managing their dogs’ weight without veterinary supervision.     

Availability, brands, labelling and salmonella contamination of raw pet food in the minneapolis/st. Paul area

The purpose of the study was to characterize the commercially available raw meat pet food diets in the Minneapolis/St. Paul area by (i) determining the number and types of available diets; (ii) assessing pet food stores and brand labels for the provision of precautionary statements regarding the risk of foodborne illness from raw meat; (ii) assessing the labels for Food and Drug Administration (FDA)/American Association of Feed Control Officials (AAFCO) required content and nutrient-related information; and (iv) culturing purchased diets for the presence of Salmonella. Sixty raw meat diets were purchased, representing 11 different brands from eight different stores. Diets were readily available in the form of raw-frozen, dehydrated or freeze-dried varieties from different protein sources, such as lamb, beef, chicken or duck. All stores promoted raw meat diets; however, none provided foodborne illness warnings. Brands varied greatly in their precautionary statements; none of the diets underwent feeding trials; and nutritional adequacy substantiation was through formulation only. The first five ingredients tended to consist of meat, organ meat (by-products), vegetables, grains and ground bones. Currently, it is required that pet foods have an AAFCO nutritional adequacy statement and provide a guaranteed analysis table. Three brands did not meet these FDA requirements. Thirty-one (51.7%) of the 60 raw meat diets underwent some degree of processing including dehydration, freeze-drying or high-pressure pasteurization. Four of the 60 raw diets (7%) tested positive for Salmonella. Analysis of raw meat pet food labels indicated a lack of foodborne illness warnings. Based on these findings, we recommend that warning statements similar to those required by the United States Department of Agriculture and placed on labels of raw meat intended for human consumption be provided on the labels of raw meat pet food diets.     

Survey of copper and zinc concentrations in commercially available dry ferret diets

BackgroundTo survey macronutrients and two micronutrients (copper and zinc) in commercial ferret diets to investigate dietary factors that may influence copper-associated hepatopathy in ferrets.MethodsProximate analysis and copper and zinc concentrations of 12 commercially available dry adult maintenance ferret diets. Medians were calculated on a dry matter and metabolizable energy basis and compared to the Association of American Feed Control Officials (AAFCO) nutrient profiles for cats and the National Research Council (NRC) recommendations for mink.ResultsCalculated metabolizable energy of diets ranged from 3830 to 4305 kcal/kg dry matter (DM). Crude protein ranged from 89.1 to 151.4 g/1000 kcal, nitrogen-free extract ranged from 13.9 to 124.7 g/1000 kcal, and crude fat ranged from 29.6 to 52.4 g/1000 kcal. The median copper concentration was 9.0 mg/1000 kcal and 37.8mg/kg DM, 7 times the AAFCO minimum for cats and 6.3 times the recommendation for mink. Median zinc concentration was 64.2 mg/1000 kcal and 243.1mg/kg DM, 3.4 times the AAFCO minimum for cats and 3.7 times the NRC recommendation for mink. The median zinc to copper ratio was 6.7.Conclusions and Clinical RelevanceThere is considerable variation in micro- and macronutrient composition among tested commercial ferret diets. High copper concentrations in ferret diets may contribute to copper-associated hepatopathy in ferrets.     

The effect of crude fibre on apparent digestibility and digestible energy content of extruded dog foods

The apparent digestibility of nutrients and energy of 38 commercial dry extruded dog foods was measured using six adult (2 to 3 year-old) female Beagles. Diets contained [in g/kg dry matter (DM)]: 164–360 crude protein (CP); 79–261 ether extracts (EE); 8–33 crude fibre (CF) and 318–585 nitrogen free extracts (NFE). Apparent energy digestibility ranged from 77.3 to 91.6%, and was closely related to CF content ( r =–0.85), yielding the resultant equation: GED (%)=94.00 – 4.04 × CF (% DM). The estimation of digestible energy content of foods from digestibility coefficients predicted from the above equation and gross energy measured or estimated from the Weende fractions, provides a more accurate prediction of experimental values than the Atwater approach followed by the National Research Council and the Association of American Feed Control Officials.     

The feline iodine requirement is lower than the 2006 NRC recommended allowance*,†,‡

The purpose of this study was to determine the iodine (I) requirement in adult cats. Forty‐two healthy euthyroid cats (1.6–13.6 years old) were utilized in a randomized complete block design. Cats were fed a dry basal diet (0.23 mg/kg I) for a minimum of 1 month (pre‐test) then switched to a different basal diet supplemented with seven levels of KI for 1 year (experimental period). Analysed I concentrations were 0.17, 0.23, 0.47, 1.1, 3.1, 6.9 and 8.8 mg I/kg diet [dry matter (DM) basis] and used to construct a response curve. Response variables included I concentrations in serum, urine and faeces, urinary I:creatinine ratio, I balance, technetium^99m pertechnetate (Tc^99m) thyroid:salivary ratio, complete blood count and serum chemistries as well as serum thyroid hormone profiles. No significant changes in food intake, weight gain or clinical signs were noted. Serum I, daily urinary I, daily faecal I and urinary I:creatinine ratio were linear functions of iodine intake. An estimate of the I requirement (i.e. breakpoint) was determined from regression of Tc^99m thyroid:salivary ratio (scintigraphy) on I intake at 12 months [0.46 mg I/kg diet (DM basis) as well as 9 months I balance (0.44 mg I/kg diet (DM)]. The I requirement estimate determined in our study at 12 months for adult cats (0.46 mg I/kg) was higher than current Association of American Feed Control Officials (AAFCO) recommendations (e.g. 0.35 mg I/kg), but was lower than the 2006 National Research Council (NRC) I recommended allowance (e.g. 1.4 mg I/kg).     

Amino acid digestibility and digestible indispensable amino acid score-like values of black soldier fly larvae fed different forms and concentrations of calcium using the precision-fed cecectomized rooster assay

Black soldier fly larvae (BSFL) are an alternative protein source for animals, including dogs and cats. Dietary calcium source is an essential nutrient for BSFL development in the pupal stage. Calcium carbonate (CaCO₃) and calcium chloride (CaCl₂) are common calcium sources but differ in solubility, acid-binding capacity, and calcium concentration. A high calcium concentration in BSFL may affect how well nitrogen and amino acids (AA) are digested by animals consuming them, thereby affecting feed conversion efficiency. Our objective was to determine the effects of dietary calcium form and concentration on nutrient composition, AA digestibility, and digestible indispensable amino acid score (DIAAS)-like values of BSFL intended for use in animal feeds using the precision-fed cecectomized rooster assay. All BSFL tested in this study were harvested at 18 d after hatch. Industry standard rearing conditions were maintained and a commercial layer ration was fed to all BSFL until 11 d post-hatch. From day 11 to 18, BSFL were fed a combination of distiller’s dried grains with solubles from a distillery, bakery byproduct meal, and varied calcium sources. All BSFL diets contained 0.2% calcium in the basal diet plus additional calcium in the following amounts and forms: BSFLA: 1.2% CaCl₂, BSFLB: 1.2% CaCO₃, BSFLC: 0.75% CaCO₃, and BSFLD: 0.6% CaCO₃ + 0.6% CaCl₂. On day 18, BSFL were washed and frozen. Prior to the rooster assay, BSFL were lyophilized and ground. In total, 16 cecectomized roosters (4 roosters per substrate) were randomly assigned to test substrates. After 24 h of feed withdrawal, roosters were tube-fed 20 g of test substrates. Following crop intubation, excreta were collected for 48 h. Endogenous corrections for AA were made using five additional cecectomized roosters. All data were analyzed using a completely randomized design and the GLM procedure of SAS 9.4. Nutrient and AA digestibilities were not different among substrates. DIAAS-like values were calculated to determine protein quality according to the Association of American Feed Control Officials nutrient profiles and National Research Council recommended allowances for dogs and cats. Although AA digestibilities did not differ, those containing CaCO₃ generally had higher DIAAS-like reference values than the diet containing CaCl₂ alone (BSFLA). Aromatic AA (Phe + Tyr) and sulfur AA (Met + Cys) were often first-limiting AA. Our results suggest that calcium sources fed to BSFL did not affect AA digestibility and protein quality.     

Dietary patterns of cats with cardiac disease

OBJECTIVE: To determine nutrient intake and dietary patterns in cats with cardiac disease. DESIGN: Prospective study. ANIMALS: 95 cats with congenital cardiac disease or primary cardiomyopathy. PROCEDURES: Owners completed a standardized telephone questionnaire regarding their cat's diet and a 24-hour food recall to determine daily intake of calories, fat, protein, sodium, magnesium, and potassium. RESULTS: Of the 95 cats, 18 (19%) had a history of congestive heart failure and 73 (77%) had no clinical signs of cardiac disease. Fifty-five percent (52/95) of cats had concurrent disease. Inappetance was reported in 38% (36/95) of all cats and in 72% (68/95) of cats with a history of congestive heart failure. Most (57% [54/95]) cats received treats or table scraps on a regular basis. Approximately half the cats were receiving orally administered medications, supplements, or both. Only 34% (32/68) of owners used food to administer medications to cats. Cats consumed more than the Association of American Feed Control Officials (AAFCO) minimums for protein, sodium, potassium, and magnesium, and nearly all cats consumed more than the AAFCO minimum for fat. Daily nutrient intake was variable for all of the nutrients assessed. CONCLUSIONS AND CLINICAL RELEVANCE: Dietary intake in cats with cardiac disease was variable, but results for dietary supplement use, food use for medication administration, and treat feeding were different from those found in a similar study of dogs with cardiac disease. This information may be useful for treating and designing nutritional studies for cats with cardiac disease.     

Dog feeding test for assessing the nutritional adequacy of practical diets

The nutritive value of dog foods declared by the manufacturer as nutritionally complete and balanced can be best assessed by feeding trials with dogs. A protocol of a feeding trial has been developed and tested with working dogs fed two different commercial complete and balanced diets for 8 weeks. The parameters used for evaluating the effect of diets were general health status, body and hair coat condition, change of body weight, haematological parameters (white blood cell (WBC) count, red blood cell (RBC) count, haemoglobin, packed cell volume), and biochemical parameters in blood serum (alanine aminotransferase, urea, albumin). The trial protocol proved to be appropriate to monitor the dogs' nutritional status and to reveal differences between diets. This method of evaluation is recommended for use in supporting the nutritional claims (labelling) of dog foods.     

Determining metabolizable energy content in commercial pet foods

This study was conducted to assess the suitability of several equations for the estimation of metabolizable energy (ME) of pet foods. Sixteen canned and 31 dry cat foods and 24 dry dog foods representing the range of energy densities found in commercial adult, growth or all life stage products were evaluated in four separate experiments. In vivo ME was compared with estimates of ME generated by several previously published equations. The results indicated that the equation recommended by Association of American Feed Control Officials provided reasonable estimates of in vivo ME for both canned cat foods and dry dog foods, but proved unsuitable for dry cat foods. Better estimates were generated in each case using other published equations. Of the equations tested, the most accurate equations for estimating ME (kJ/g) without feeding trials were:
for canned cat foods: [(16.32 × protein) + (32.22 × fat) + (12.55 × NFE)];
for dry cat foods: [((GE × 1.209) – 1.911) × 4.184] or [((0.075 × g fat) + 2.766) × 4.184]
for dry dog foods: [GE=(24 × g protein) + (38 × g fat) + (17 × g NFE), then percentage energy digestibility=91.2 – (1.43 × percentage crude fibre in dry matter), then ME=(GE × percentage energy digestibility) – (4.34 × g protein)].
With the exception of high-fibre weight-management diets, the simple equation [((GE × 1.209)–1.911) × 4.184] also reliably predicted ME in dry dog foods.     

Commercial diet recommendations and follow-up for a large breed puppy with an intrahepatic portosystemic shunt

A 6-month-old, intact male Great Dane dog fed a veterinary therapeutic liver diet was evaluated after diagnosis of an intrahepatic portosystemic shunt and hind limb angular limb deformity to determine appropriateness of diet. Evaluation of the current diet revealed it to be inadequate to meet the nutrient requirements of a large breed puppy. The dog clinically improved following a change in diet. There was no longer any angular limb deformity and no reported neurological signs. This report highlights the importance of appropriate feeding management during growth and demonstrates that although veterinary therapeutic diets may appear to be an appropriate choice initially, they may not be ideal for growing puppies as a long-term feeding option.Key clinical message:An individual approach is key for nutritional management of complicated canine veterinary medical cases and includes consideration of the patient’s life stage requirements when modifying nutrient intake to manage clinical disease.     

Processing of ingredients and diets and effects on nutritional value for pigs

A conventional diet based on corn and soybean meal fed to pigs is usually provided in a mash form and in most cases, processing other than grinding and mixing is not used. However, due to the high cost of energy in pig diets,use of high fiber ingredients such as soybean hulls, distillers dried grains with solubles, and wheat middlings has increased. High fiber concentrations in the diet usually results in reduced energy and nutrient digestibility due to the low capacity of pigs to digest fiber, which negatively impacts growth performance and carcass composition of the pigs. Feed processing technologies such as changes in grinding procedures, expansion, extrusion, pelleting, use of enzymes or chemical treatments may, however, be used to solubilize some of the cel ulose and hemicel ulose fractions that form the cel wal of plants in the ingredients, and therefore, increase nutrient availability. This may have a positive effect on energy digestibility, and therefore, also on pig growth performance and carcass composition, but effects of different feed technologies on the nutritional value of feed ingredients and diets fed to pigs are not fully understood. It has however, been demonstrated that reduced particle size of cereal grains usually results in increased digestibility of energy, primarily due to increased digestibility of starch. Extrusion or expansion of ingredients or diets may also increase energy digestibility and it appears that the increase is greater in high fiber diets than in diets with lower concentrations of fiber. Chemical treatments have not consistently improved energy or nutrient digestibility, but a number of different enzymes may be used to increase the digestibility of phosphorus, calcium, or energy. Thus, there are several opportunities for using feed technology to improve the nutritional value of diets fed to pigs.     

Evaluation of dietary patterns in dogs with cardiac disease

OBJECTIVE: To determine the dietary patterns and intake of nutrients of concern in dogs with cardiac disease. DESIGN: Prospective study. ANIMALS: 82 dogs with dilated cardiomyopathy (DCM) or chronic valvular disease. PROCEDURE: Owners of dogs were contacted and given a standardized telephone questionnaire regarding diet and a 24-hour food recall to determine daily intake of calories, protein, fat, sodium, potassium, and magnesium. RESULTS: Among the 82 dogs, 71% had no congestive heart failure (CHF), and 29% had CHF or a history of CHF. Sixty-one percent of dogs had concurrent diseases. Anorexia was or had been evident in 34% of dogs and was significantly more common in the CHF group and in dogs with DCM. Most dogs (92%) received some treats and table food, with a median percentage of daily calories from treats of 19% (range, 0% to 100%). Most owners (57%) that administered pills used human or pet foods for pill administration. Most dogs ate more than the Association of American Feed Control Officials (AAFCO) minimum values for fat and protein. Daily sodium intake varied from 14 to 384 mg/100 kcal, compared with the AAFCO minimum of 17 mg/100 kcal. A median of 25% of total daily sodium came from treats and table food (range, 0% to 100%). Dogs with CHF ate significantly more sodium, compared with dogs with no CHF. CONCLUSIONS AND CLINICAL RELEVANCE: Dietary intake for dogs with cardiac disease is highly variable and often not optimal.     

Sand intake by laying hens and its effect on egg production parameters

Soil intake may be the most prominent source of environmental contaminants for free range and organic hens, but there are no quantitative data concerning soil intake by domestic hens. Consumption of soil of 14–32 g a day can be estimated from literature, but such a dilution of nutrient intake seems incompatible with high productivity. In this study laying hens were fed pelleted diets with 0%, 10%, 20%, 25% and 30% of sand addition to determine its effect on productivity. Feed intake, feed and nutrient (feed minus sand) conversion ratio, egg production, egg weight and body weight gain were measured over a 4-week period. Acid insoluble ash concentration in the faeces was measured to determine the accuracy of estimating the soil ingestion by the soil-ingestion equation for wildlife as a way to determine soil ingestion of free range and organic hens under practical circumstances. The hens were able to compensate the dilution of the diet with 20%, 25% and 30% of sand by increasing their feed intake. Feed intake increased significantly and feed to egg conversion ratio decreased significantly with increasing sand levels in the diet. The nutrient to egg conversion ratio of the diet without sand tended to be worse than for the diets with sand, presumably due to the total absence of coarse material in the diet. There were no differences in egg production and egg weight between hens fed the different diets but body weight gain was significantly lower for the hens fed the diets with 20%, 25% and 30% of sand. Estimation of sand ingestion was done by the soil-ingestion equation for wildlife. Provided that the actual dry matter digestibility coefficient of the nutrient part of the diet is taken into account, estimating the soil ingestion according to the soil-ingestion equation for wildlife seems an appropriate way to determine soil ingestion for free range and organic hens under practical circumstances.     

Evaluation of supplementary stevia (Stevia rebaudiana,bertoni) leaves and stevioside in broiler diets: effects on feed intake,nutrient metabolism,blood parameters and growth performance

A perennial schrub, stevia, and its extracts are used as a natural sweetener and have been shown to possess antimicrobial properties. Stevia contains high levels of sweetening glycosides including stevioside which is thought to possess antimicrobial and antifungal properties. Little is known about the nutritional value of the schrub in livestock. This study determined the potential use of the shrub as a prebiotic animal feed supplement in light of the recent ban on the use of antibiotics in animal feed and the role of its constituent stevioside in the effects of the shrub. Male Cobb broiler chicks were fed a basal broiler diet without antibiotic but with performance enhancing enzyme mix (positive control), a basal diet without antibiotic and enzymes (negative control), or diets in which 2% of the negative control diet was replaced with either dried ground stevia leaves or 130 ppm pure stevioside during 2 week starter and 2 week grower periods. Body weight gains, feed conversion, abdominal fat deposition, plasma hormone and metabolites and caecal short chain fatty acids (SCFA) were measured in the broilers at 2 and 4 weeks of age. There was no significant effect of the treatments on feed intake during the starter period but birds fed diet supplemented with stevia leaves and stevioside consumed more feed (p < 0.05) than those fed the positive control diet during the grower period. Weight gain by birds fed the positive control and stevioside diets was higher (p < 0.05) than those fed other diets only during the starter period. Feed/gain ratio of birds fed the positive control and stevioside diets was superior (p < 0.05) to others. There was no effect of the treatments on nutrient retention and water content of the excreta. Dietary stevia leave and stevioside decreased total concentration of SCFA and changed their profile in the ceca. There was no effect of the treatments on pancreas weight. Dietary stevia reduced blood levels of glucose, triglycerides and triiodothyronine (T₃) but had no effect on non-esterified fatty acids. In contrast, stevioside only decreased T₃. Both the stevia leaves and stevioside diets significantly increased abdominal fat content. It is concluded that dietary enzyme growth promoters are beneficial to the broilers only during the starter stage and that inclusion of stevia leaves or stevioside has no beneficial effect on the performance of broilers.     

A comparison of certified and noncertified pet foods.

The market presents the buyer with a wide array of pet food choices. Marketing pet foods has changed in the last decade and today foods may be bought at a variety of outlets. The present study compares nutrient composition, digestibility, and effect on urine pH (cat foods only) of selected certified and noncertified pet foods from different outlets. The selected foods were considered analogous in terms of declared ingredients and macronutrient profiles. The analytical methods used were those of the Association of Official Analytical Chemists as described in the Pet Food Certification Protocol of the Canadian Veterinary Medical Association. The test foods were sampled 4 times from August 1994 to July 1995. Both certified and noncertified products met the nutritional requirements on a consistent basis, although 1 of the noncertified dog foods consistently failed to meet the zinc requirements. This same product also failed to meet the Canadian Veterinary Medical Association's standards for concentrations of protein, calcium, and phosphorus. One of the noncertified cat foods failed to meet the recommended calcium level. With the exception of fat digestion in 1 noncertified food, there were no statistically significant differences in major nutrient digestibility between certified and noncertified pet foods. There were some statistically significant differences in digestibility within both the certified and noncertified groups of foods. The practical significance of any of the statistical differences in digestibility is uncertain. Urine pH observed in cats fed noncertified test diets was variable, with some values greater than 7.0 as a maximum or 6.5 as an average. The general conclusion of this study was that the commonly available certified products were the nutritional equal of those foods that position themselves as "premium."     

Soybean hulls as a dietary fiber source for dogs.

In Exp. 1, soybean hull samples were obtained from nine sources across the United States and analyzed for nutrient content to determine their suitability for inclusion in dog diets. Compositional data revealed variation in both the amount of total dietary fiber (TDF; 63.8 to 81.2%) in the soybean hulls and the ratio of insoluble:soluble fiber (5.0:1 to 15.4:1). Crude protein content varied widely among sources, ranging from 9.2 to 18.7%. An in vivo trial (Exp. 2) was conducted using a premium dog diet containing 3.0, 4.5, 6.0, 7.5, or 9.0% soybean hulls (DM basis). There was a negative linear effect (P < .05) of soybean hull inclusion in the diet on DM, OM, TDF, and GE total-tract digestibilities, as well as on calculated ME. Crude protein and fat digestibilities were unaffected by treatment. Based on these results, ileally cannulated dogs were fed diets containing 6.0, 7.5, or 9.0% soybean hulls (DM basis) in addition to diets containing either 0% supplemental fiber or 7.5% beet pulp (Exp. 3). Nutrient digestion at the ileum was unaffected by inclusion of supplemental fiber. Total tract digestion of DM, OM, and GE was lower ( P < .05) for diets containing supplemental fiber when compared with the diet containing 0% fiber. Crude protein and fat digestibilities were unaffected by treatment. There was no difference in nutrient digestibility between those diets containing soybean hulls and a diet containing beet pulp. Soybean hull inclusion in the diet resulted in a negative linear effect (P < .05) on calculated ME, in addition to lowering ME (P < .05) when compared with the 0% fiber control diet. Calculated ME for dogs fed a 7.5% beet pulp-containing diet was lower (P < .05) than that for dogs fed the soybean hull-containing diets. Results indicate that soybean hulls can be an effective dietary fiber source in dog diets.     

Effect of exogenous enzymes in maize-based diets varying in nutrient density for young broilers: growth performance and digestibility of energy, minerals and amino acids

1. A total of 192 male broilers (Cobb 500) were used in a growth and digestibility assay, involving a 2 x 2 factorial arrangement of treatments, to assess the effects of an enzyme cocktail of xylanase, amylase and protease in maize-based diets. 2. The following two diets were formulated: a positive control diet containing adequate nutrient concentrations for broiler starters as per breeder recommendations and a negative control diet to contain approximately 0.63 MJ/kg apparent metabolisable energy (AME) and 3% amino acids less than the positive control. 3. A further two dietary treatments were developed by supplementing each control diet with an enzyme product containing xylanase, amylase and protease. 4. Birds fed on the negative control diet had poorer weight gain and feed efficiency than those given the positive control diet. There was no effect of diet or enzyme on feed intake. The digestibility of nitrogen, calcium, phosphorus and most amino acids were unaffected by dietary nutrient density. 5. Supplementation of both the positive and negative control diets with the enzyme improved weight gain and feed efficiency compared with the unsupplemented diets. In the case of the negative control, supplemental enzyme improved performance to that of the unsupplemented positive control diet. There was no interaction between diet and enzyme for either weight gain or FCR, suggesting similar beneficial responses regardless of the nutrient density of the diet. 6. In both diets, enzyme supplementation improved AME by an average of 3% (0.35 MJ/kg DM) and nitrogen retention by an average of 11.7% (26 g/kg DM intake vs 29 g/kg DM intake). There was no interaction between diet and enzyme for AME or nitrogen retention. 7. Ileal digestibilities of calcium and phosphorus were not influenced by supplemental enzyme, whereas the digestibility of nitrogen and most amino acids was improved by enzyme addition compared with the unsupplemented control diets. There was no interaction between diet and enzyme for the ileal digestibility of nitrogen and amino acids. 8. These data demonstrate that it is possible to improve the nutritional value of a maize/soy-based diet for broiler starters through the use of exogenous enzymes. The nutrient density of the diet does not appear markedly to influence the response to enzyme, offering flexibility in the use of enzymes for maize-based diets. 9. It is concluded that the energy and amino acid values of maize-based diets for broilers can be enhanced by supplementation with an enzyme cocktail of xylanase, amylase and protease, offering potential economic benefits to producers.