Evaluation of standardized ileal digestibility of amino acids and metabolic availability of methionine, using the indicator amino acid oxidation method, in black soldier fly larvae (Hermetia illucens) meal fed to growing pigs.

Standardized ileal digestibility (SID, %) of crude protein (CP) and amino acid (AA) and the metabolic availability (MA) of Met using the indicator amino acid oxidation (IAAO) method, in partially defatted black soldier fly larvae (PD-BSFL) meal were determined in growing pigs in 2 experiments. The Met SID value was then compared numerically with the Met MA to understand how different SID is compared with its MA value. In Exp. 1, 6 ileal-cannulated barrows (initial body weight [BW] = 18.03 ± 0.34 kg) were used in a 2-period switch back design and fed either a nitrogen-free diet (NFD) or test diet, with PD-BSFL meal as the sole source of AA, over two 11-d experimental periods, at a feeding level of 2.8 × estimated maintenance digestible energy requirement. Barrows were adapted for 9-d to the diet, followed by continuous 8-h ileal digesta collection on day 10 and 11. Digesta were pooled per pig within period. The SID of CP and Met of PD-BSFL meal were 76.1 ± 6.2% and 90.4 ± 3.9%, respectively. In Exp. 2, 7 barrows (initial BW = 18.77 ± 0.69 kg) were used in a 7 × 7 Latin square design with L-[1-13C]-Phe as the indicator AA. Each pig was randomly assigned to 1 of 7 dietary treatments over seven 3-d experimental periods. Two diet types were studied including reference (crystalline AA) and PD-BSFL test diets, each supplying graded intakes of Met at 55, 65, and 75% of the estimated SID requirement (NRC, 2012). The MA of Met was determined by comparing the IAAO response between the reference and PD-BSFL test diet using the slope-ratio method. Linear regression determined a negative slope of the best fit line for both the reference and test diets (P < 0.05). The MA of Met in PD-BSFL meal was 53.3%, which is as expected lower than the SID value. While it is generally appreciated that MA will be less than SID, the use of SID is more practical. In cases where SID cannot explain physiological outcomes of feeding a novel ingredient, IAAO may provide additional insight into whether MA should be explored.

The interest in black soldier fly larvae (BSFL) meal as a protein ingredient in swine feed has grown in the past years. As a novel protein ingredient, it is beneficial to evaluate the amino acid (AA) digestibility and metabolic availability (MA) of the limiting AA, Met, in pigs, in BSFL meal prior to incorporation in feed for a more precise formulation. Two different methodologies were used to determine the AA digestibility and MA, standardized ileal digestibility (SID) and indicator amino acid oxidation (IAAO) method, respectively. Based on the SID values, the AA digestibility of BSFL meal, for some, but not all AA, is comparable to other commonly used protein ingredients in commercial swine feed. When compared with the MA result of Met, the Met SID value is much lower. This indicates that not all digested Met is available for protein synthesis or other metabolic processes in the animal.

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.

Équations utilisées pour élaborer des lignes directrices commerciales sur l'alimentation des chiens et les pratiques d'alimentation des propriétaires canadiens en 2018. Les directives d'alimentation sur les emballages commerciaux d'aliments pour chiens fournissent un point de départ suggéré pour l'approvisionnement en nourriture des chiens. Les équations utilisées pour élaborer des lignes directrices commerciales sur l'alimentation des chiens et les pratiques d'alimentation des propriétaires sondées ont été examinées dans cette étude. Les équations utilisées pour élaborer des lignes directrices sur l'alimentation et la méthode de calcul de la densité énergétique (équation Atwater traditionnelle ou Atwater modifiée) ont été étudiées pour 200 aliments secs pour chiens vendus au Canada. Toutes les densités énergétiques des produits n'ont pas été calculées à l'aide de l'équation Atwater modifiée, une exigence si l'on prétend être conforme à l'Association of American Feed Control Officials (AAFCO). Les directives d'alimentation commerciales fournissent des estimations prudentes des besoins énergétiques des chiens de compagnie. Une enquête sur les pratiques alimentaires des propriétaires de chiens a été menée, avec 739 réponses analysées. Les répondants ont généralement pris les mesures appropriées pour gérer le poids de leurs chiens par l'exercice et la gestion de l'alimentation. Une enquête plus approfondie devrait explorer comment les propriétaires peuvent gérer avec succès le poids de leurs chiens sans surveillance vétérinaire.(Traduit par Dr Serge Messier).

The daytime feeding frequency affects appetite-regulating hormones, amino acids, physical activity, and respiratory quotient, but not energy expenditure, in adult cats fed regimens for 21 days.

The effects of feeding frequency on postprandial response of circulating appetite-regulating hormones, insulin, glucose and amino acids, and on physical activity, energy expenditure, and respiratory quotient were studied in healthy adult cats. Two experiments were designed as a 2 x 3 replicated incomplete Latin square design. Eight cats, with an average body weight (BW) of 4.34 kg ± 0.04 and body condition score (BCS) of 5.4 ± 1.4 (9 point scale), were fed isocaloric amounts of a commercial adult maintenance canned cat food either once (0800 h) or four times daily (0800 h, 1130 h, 1500 h, 1830 h). Study 1 consisted of three 21-d periods. On day 14, two fasted and 11 postprandial blood samples were collected over 24 hours to measure plasma concentrations of ghrelin, GLP-1, GIP, leptin, PYY, insulin and amino acids, and whole blood glucose. Physical activity was monitored from day 15 to 21 of each period. In Study 2 indirect calorimetry was performed on the last day of each period. Body weight was measured weekly and feed intake recorded daily in both experiments. No effect of feeding regimen on BW was detected. Cats eating four times daily had lesser plasma concentrations of GIP and GLP-1 (P<0.05) and tended to have lesser plasma PYY concentrations (P<0.1). Plasma leptin and whole blood glucose concentrations did not differ between regimens (P>0.1). Cats fed once daily had a greater postprandial plasma amino acid response, and greater plasma ghrelin and insulin concentrations (P<0.05). Physical activity was greater in cats fed four times (P<0.05), though energy expenditure was similar between treatments at fasting and in postprandial phases. Finally, cats eating one meal had a lower fasting respiratory quotient (P<0.05). Overall, these data indicate that feeding once a day may be a beneficial feeding management strategy for indoor cats to promote satiation and lean body mass.

Comparison of methodologies used to define the protein quality of human foods and support regulatory claims.

Protein quality (PQ) is the capacity of a protein to meet the amino acid (AA) requirements of an individual. There are several methodologies for determining the PQ of foods. The protein efficiency ratio is an animal growth bioassay. The protein-digestibility-corrected AA score considers the AA requirements of a reference population, and the true nitrogen digestibility coefficient for each ingredient. The digestible indispensable AA score is based on true ileal AA digestibility and better represents bioavailability of AAs. In vitro techniques for assessment of PQ are available but require validation against a greater range of protein sources. Isotopic methods, such as the indicator AA oxidation and dual tracer techniques measure AA relative bioavailability and digestibility, respectively, but require sophisticated equipment, and may not be cost nor time effective for the industry to adopt. The present review discusses advantages and disadvantages of methodologies for determining PQ of food for humans focused on methods that are or could be adopted by regulatory agencies. Understanding the framework and resources available for PQ determination will help in the selection of appropriate methods depending on the application. Novelty Understanding the framework and resources available for PQ determination will help in the selection of appropriate methods depending on the application.

Effects of incremental exercise and dietary tryptophan supplementation on the amino acid metabolism, serotonin status, stool quality, fecal metabolites, and body composition of mid-distance training sled dogs.

Exercise improves the health of dogs; however, the extreme exertion experienced by sled dogs may lead to variable metabolic and fecal characteristics. Nutritional interventions, such as dietary tryptophan (Trp), may reduce the prevalence of these exercise-induced disturbances. Sporting diets tend to have high crude protein concentrations in contrast to adult maintenance diets and this results in less Trp relative to other amino acids (AA). Therefore, sporting dogs represent an ideal cohort to assess the effects of supplemental Trp. The objective was to evaluate the effects of supplemental dietary Trp and an incremental training regimen on AA and serotonin status, fecal scores and metabolites, and body composition in client-owned Siberian huskies. Sixteen dogs (nine females and seven males) were used, with a mean age of 4.8 ± 2.5 yr and body weight (BW) of 24.3 ± 4.3 kg. Dogs were blocked for sex, age, and BW and randomly allocated into two groups with eight fed a dry extruded control diet (Ctl) and eight fed Ctl supplemented with Trp to reach a Trp:large-neutral AA (LNAA) ratio of 0.075:1 (treatment, Trt). The exercise regimen was designed to increase in distance each week, but weather played a role in setting the daily distance. Each week BW was recorded and food allotments were adjusted to maintain initial BW. Pre and post-exercise blood samples were taken every 3 wk, dogs then received a meal followed by 1, 2, and 4 h post meal blood collections (serum AA, serotonin). Stool collection and scoring occurred each week and body composition was measured on weeks -1 and 11. Serotonin, AA, fecal metabolite, and body composition data were analyzed using PROC MIXED of SAS with dog as a random effect and week and Trt as fixed effects. Stool score data were analyzed using PROC FREQ to compare stool score and Trt, and PROC CORR was used to analyze associations between fecal score, temperature, humidity, and run distance. Dogs on Trt had greater fasted Trp compared with baseline, greater post-meal Trp and serotonin compared with baseline, greater post-meal Trp compared with fasted, and greater post-meal Trp and serotonin compared with Ctl (P < 0.05). Fecal data indicated that Trp improved stool scores (P < 0.05) yet had no effect on fecal metabolites. An overall increase in lean and decrease in fat mass was found (P < 0.05), but Trt had no effect on body composition. Optimization of the dietary Trp:LNAA ratio may help to improve GI health without compromising performance in actively training sled dogs.

Apparent and true digestibility of macro and micro nutrients in adult maintenance dog foods containing either a majority of animal or vegetable proteins1.

There is dearth of knowledge with regards to mineral digestibility of ingredients in canines, and current knowledge is focused on the digestibility of supplemented minerals, not on intrinsic mineral digestibility of ingredients. The objectives of the present study were to determine the apparent and true digestibility (TD) of macronutrients and micronutrients, and the total tract gastrointestinal endogenous nutrient outputs in canines fed either animal- or vegetable-based adult maintenance diets. Eight purpose bred Beagles (two intact males, six spayed females) of similar age (2.12 ± 0.35 yr, mean ± SD) and weight (9.92 ± 0.73 kg, mean ± SD) were pair housed in kennels but fed individually based on individual maintenance energy requirements. Two basal diets (animal and vegetable protein based) were formulated to meet nutritional requirements of adult canines. Two additional trial diets were created, using the basal diets, by diluting diets by 50% with anhydrous α-d-glucose to attempt to quantify endogenous mineral losses and enable calculation of TD. All diets contained titanium dioxide at 0.3% for calculations of nutrient digestibility. Dogs were provided with deionized water as their only source of water throughout the trial. Dogs in a specific kennel were randomly assigned to an experimental diet for 10 d (experimental period), and fecal samples were collected the last 4 d of each period. All dogs were fed all experimental diets in random order based on a 4 × 4 replicated Latin square design. Dogs fed intact diets had a higher apparent mineral digestibility compared to dogs fed diluted diets (P < 0.05). Apparent phosphorus digestibility was higher for dogs fed the diet 2 compared with the diet 1 (P = 0.01) and the diluted diets (P < 0.001). There was a trend towards a greater TD of Cu for dogs fed the diet 2 compared with the diet 1 (P = 0.08). P, Mg, Zn, and Mn true digestibilities were higher for dogs fed the diet 2 compared with the diet 1 (P < 0.05, P = 0.01, P = 0.02, P = 0.009, respectively). These results suggest that apparent and TD do not result in similar values. Further research should be conducted on TD in canines only if a better model is developed.

Canine Food Preference Assessment of Animal and Vegetable Ingredient-Based Diets Using Single-Pan Tests and Behavioral Observation.

Knowledge of canine food selection is critical for both the pet food industry and dog owners, since owners want quality foods that are palatable, while fulfilling their pet's nutritional requirements. There are two common methods for assessing canine food preference: the two-pan test and the one-pan test. Neither test fully accounts for the complexity of the canine feeding experience nor do they provide applicable representations of canine feeding behavior in the home. The objectives of this study were to (1) determine whether dogs display a preference for animal ingredient-based diets when compared with vegetable ingredient-based diets and (2) examine whether dogs experience neophobia when presented with a novel diet. Eight adult Beagles (average age = 24 months, weighing 8-12 kg) were individually fed each of four novel diets in a 4 × 4 replicated Latin square design, with 10-d treatment periods and four dietary treatments. Data were analyzed using a mixed model with repeated measures and significance was declared when p < 0.05. The diets were: animal and vegetable ingredient-based diets, and animal- and vegetable-based ingredients diluted with anhydrous α-d-glucose. The diluted diets were used for a larger study to determine true mineral digestibility. Dogs were fed twice per day (0800 and 1300 h). Behavioral observations were made by video on the first, and last 2 days of each 10-day treatment period of both a.m. and p.m. feedings. Time to consume feed, distraction, hesitation, level of anticipation pre-consumption, and interest post-consumption were recorded. Dogs experienced initial disruptive (neophobic) effects of a novel diet. Neophobia was demonstrated by a decreased (slower) rate of consumption, increased distraction during consumption of the diet, and increased hesitation on the first day of each new diet (p < 0.05). The level of interest post-consumption was highest when dogs consumed the animal-based ingredients diet (p < 0.05). This study presents insights into canine food preference assessment methods that may more accurately represent the dog owner's experience. Further research is required to determine the minimum length of time necessary to eliminate neophobia to food. In addition, future research should also aim to establish whether interest post-consumption is due primarily to food preference or acute satiety.