Macronutrient composition, true metabolizable energy and amino acid digestibility, and indispensable amino acid scoring of pulse ingredients for use in canine and feline diets

Abstract

The rising consumer demand for alternative and sustainable protein sources drives the popularity of the use of plant-based proteins in the pet food industry. Pulse crops, which include beans, peas, lentils, and chickpeas, have become an important addition to both human and animal diets due to their protein content and functional properties. However, knowledge of their nutrient composition and protein quality is necessary for the proper formulation of these ingredients in pet foods. The objective of this study was to determine the macronutrient composition and standardized amino acid digestibility and to describe the protein quality through the use of digestible indispensable amino acid scores (DIAAS-like) of five pulse ingredients. Black bean (BB) grits, garbanzo beans (GB), green lentils (GL), navy bean (NB) powder, and yellow peas (YP) were analyzed for dry matter (DM), ash and organic matter (OM), crude protein (CP), gross energy (GE), acid hydrolyzed fat (AHF), and total dietary fiber (TDF) to determine the macronutrient composition. Precision-fed rooster assays were conducted using cecectomized roosters to calculate standardized amino acid digestibility and true metabolizable energy corrected for nitrogen (TMEn). The essential amino acids, with the exception of methionine, were highly digestible with digestibility values of 80% to 90% (dry matter basis) for all selected pulse ingredients. BB grits had the lowest (P < 0.05) digestibility of arginine (86.5%) and histidine (80.6%) in contrast to GB (94.9% and 89.9%, respectively). The TMEn of GB was highest (P < 0.05) at 3.56 kcal/g compared with the other pulses. The DIAAS-like values for adult dogs were consistently the lowest for methionine for all pulses, making it the first-limiting amino acid in these ingredients. The DIAAS-like values for adult cats showed GL had lowest (P < 0.05) score in tryptophan compared with other pulses when using both AAFCO values and NRC recommended allowances as reference proteins. Methionine was the first-limiting amino acid for YP and tryptophan for GL. Based on macronutrient composition, protein quality, and amino acid digestibility, it can be concluded that pulse ingredients have the required nutritional characteristics to be viable protein sources in canine and feline foods. However, the use of complementary protein sources is recommended to counterbalance any potential limiting amino acids in pulse ingredients.

Short-term amino acid, clinicopathologic, and echocardiographic findings in healthy dogs fed a commercial plant-based diet

“…The nutritive content and digestibility of PB ingredients commonly used in commercial pet foods have been studied extensively [ 9 – 13 ], and it is well-established that PB ingredients can serve as viable sources of energy, dietary fiber, digestible carbohydrates, and a variety of other essential and non-essential nutrients for dogs [ 2 , 14 ]. In recent years, consumer demand for alternative protein sources has prompted researchers to investigate amino acid (AA) digestibility and protein quality of several PB ingredients, such as pulses (e.g., beans, lentils), protein concentrates (e.g., pea protein, potato protein), and soy [ 15 – 18 ]. Using precision-fed rooster assays, Reilly and colleagues demonstrated high digestibility of all the indispensable AAs, except methionine, in selected pulse ingredients and high digestibility of all the indispensable AAs in PB protein concentrates [ 15 , 16 ].…”

“…In recent years, consumer demand for alternative protein sources has prompted researchers to investigate amino acid (AA) digestibility and protein quality of several PB ingredients, such as pulses (e.g., beans, lentils), protein concentrates (e.g., pea protein, potato protein), and soy [ 15 – 18 ]. Using precision-fed rooster assays, Reilly and colleagues demonstrated high digestibility of all the indispensable AAs, except methionine, in selected pulse ingredients and high digestibility of all the indispensable AAs in PB protein concentrates [ 15 , 16 ]. Protein quality, assessed by digestible indispensable amino acid scores (DIAAS), indicated methionine was the first-limiting AA in all the pulse ingredients and in all but one of the protein concentrates tested [ 15 , 16 ].…”

“…Using precision-fed rooster assays, Reilly and colleagues demonstrated high digestibility of all the indispensable AAs, except methionine, in selected pulse ingredients and high digestibility of all the indispensable AAs in PB protein concentrates [ 15 , 16 ]. Protein quality, assessed by digestible indispensable amino acid scores (DIAAS), indicated methionine was the first-limiting AA in all the pulse ingredients and in all but one of the protein concentrates tested [ 15 , 16 ]. These findings suggest some PB ingredients are viable protein sources for canine and feline diets and emphasize the importance of inclusion of complementary proteins when formulating diets rich in certain PB ingredients.…”

Digestible indispensable amino acid scores of animal and plant ingredients potentially used in dog diet formulation: how this protein quality metric is affected by ingredient characteristics and reference amino acid profile

“…Fundamentally, the most appropriate IAA reference patterns to apply for dogs are based on MR estimates established by the NRC (2006) for adult dogs and growing puppies, as these represent physiological IAA requirements. Though, based on the pet food industry’s reliance on practical dietary IAA recommendations presented by AAFCO and FEDIAF as well as the recent literature reporting “DIAAS-like” values for dog food ingredients calculated using reference patterns based on IAA recommendations from these regulatory bodies ( Oba et al, 2019 ; Do et al, 2020 ; Reilly et al, 2020a , 2020b , 2021 ; Gomez et al, 2021 ), we sought to assess the degree to which using these reference patterns may affect the PQ interpretation.…”

“…In brief, what this suggests is that, yes, using reference IAA patterns based on these AAFCO or FEDIAF recommendations will generate different DIAAS-like values than those determined using NRC MR estimates; however, these data must be interpreted with caution as these reference patterns no longer represent the physiological requirements of the dog, but rather account for assumed digestibility of the protein source. That being acknowledged, with the propensity of the pet food industry to rely on the recommendations presented by AAFCO and FEDIAF for commercial formulation purposes, and with the recent literature assessing PQ of ingredients intended for dog diet formulation using reference IAA patterns based on these regulatory bodies ( Oba et al, 2019 ; Do et al, 2020 ; Reilly et al, 2020a , 2020b , 2021 ; Gomez et al, 2021 ), it may be valuable to assess the extent to which using these reference patterns may affect the PQ interpretation.…”