BACKGROUND: Interest is growing in the search for alternatives to traditional feed additives, so this study aimed to investigate the effect of adding zeolite to the concentrate diets of Awassi lambs with or without urea on growth performance, nutrient digestion, and health status. A total of 45 Awassi lambs similar in weight (24 ± 2 kg) and age (3 months ± 4 days) were divided into three groups: the first group (G1) fed on a concentrate diet supplemented with 1% urea; the second group (G2) fed on the concentrate diet supplemented with 1% urea and 3% zeolite, and the third group (G3) fed on a urea-free diet supplemented with 3% zeolite.
RESULTS: The results showed a significant increase (P ≤ 0.05) in final live weight, daily and total weight gain for group G2 compared to groups G1and G3, with a significant superiority (P ≤ 0.05) of group G3 over the control group G1. Significant improvement (P < 0.05) was also observed in feed consumption and feed conversion ratio in diets supplemented with zeolite for groups G2 and G3 compared to the control group G1. Additionally, there was a significant increase (P ≤ 0.05) in nutrient digestion and nutritional value in the diet of group G2 containing urea with added zeolite compared to groups G1 and G3. Zeolite did not affect the levels of glucose, triglycerides, cholesterol, and albumin in the blood, but a significant increase (P ≤ 0.05) in total blood protein level and a significant decrease (P ≤ 0.05) in blood urea level were noted for groups G2 and G3 compared to the control group G1.
CONCLUSIONS: Adding zeolite to urea-containing concentrate diets improved growth rates and nutrient digestion, of Awassi lambs. In diets without urea, zeolite improved growth rates without affecting nutrient digestion coefficients, in both types of diets, zeolite increased total protein levels and decreased blood urea levels, with all physiological indicators in lambs blood remaining within normal limits.

The increased fish consumption by the growing human population in the world translates into an increase in fish waste. The reintroduction of these fish by-products into food and feed chains presents economic benefits and contributes to counteracting their negative environmental impact. Under this context, the present study aimed to evaluate the effects of the dietary inclusion of fish hydrolysate and oil obtained from fish waste (experimental diet) in substitution of shrimp hydrolysate and salmon oil (control diet) mainly imported from third countries on palatability, apparent total tract digestibility, fecal characteristics and metabolites, blood fatty acid profile, flatulence, and coat quality of adult dogs. A two-bowl test was performed to evaluate palatability by the pairwise comparison between the two diets. A feeding trial was conducted according to a crossover design with two diets (control and experimental diets), six adult Beagle dogs per diet, and two periods of 6 weeks each. The replacement of shrimp hydrolysate and salmon oil with fish hydrolysate and oil did not affect the first diet approach and taste, as well as the intake ratio. Generally, the digestibility of dry matter, nutrients, and energy was not affected by diet, but the intake of digestible crude protein (CP) and ether extract was higher, respectively, with the control and the experimental diet. The higher intake of eicosapentaenoic acid and docosahexaenoic acid with the experimental diet was reflected in a higher content of these long-chain polyunsaturated fatty acids and the omega-3 index of red blood cells, but it did not affect coat quality. The significantly higher intake of digestible CP with the control diet might have contributed to the higher fecal ammonia-N and valerate concentrations. Daily fecal output and characteristics were similar between diets. Overall, results suggest that fish hydrolysate and oil from the agrifood industry might constitute sustainable functional ingredients for dog feeding while adding value for wild fisheries, aquaculture, and fish farming under a circular economy approach and reducing dependence on imports from third countries with a high carbon footprint.

This study conducted a comparison of the effects of non-protein nitrogen with different acid-base properties on feed intake, rumen fermentation, nutrient digestion and antioxidant capacity in fattening Hu sheep. Sixteen fattening male sheep (31.43 ± 2.41 kg) with permanent rumen cannulas were randomly assigned to two dietary treatments: 1% urea and 1.78% ammonium chloride (NH4Cl, AC). A 42 days experimental period was conducted, with 14 days for adaptation and 28 days for treatment. Daily feed intake was recorded and various samples including feed, feces, rumen fluid, and blood were collected at different time points during the final week. The results indicated that the urea group had significantly higher dry matter intake, average daily gain, and gain efficiency in comparison to the AC group (p < 0.01). There was no difference in rumen pH and concentration of ammonia nitrogen between different groups (p > 0.05), but the rumen pH of urea group was higher than that of the AC group at 1 and 3 h after feeding (p < 0.05). The urea group exhibited higher concentrations of total volatile fatty acids (VFA) and individual VFAs compared to the AC group at all-time points (p < 0.01). Compared to the urea group, the intake of all nutrients decreased in the AC group (p < 0.01), but the digestibility of dry matter and organic matter increased significantly (p < 0.01), and the digestibility of CP had an increasing trend (p = 0.06) in the AC group. Additionally, the urea group had lower levels of serum glucagon-like peptide-1, peptide YY, Cl, total protein and globulin than the AC group (p < 0.05). The overall levels of HCO3-, superoxide dismutase, glutathione peroxidase, catalase, albumin/globulin, blood urea nitrogen and total cholesterol in the urea group increased significantly compared to the AC group (p < 0.05). It was concluded that adding urea to the high-concentrate diet resulted in increased rumen pH and improved rumen fermentation and growth performance in fattening sheep compared to NH4Cl addition. Furthermore, urea addition improved sheep\'s antioxidant capacity and maintained their acid-base balance more effectively as compared to NH4Cl.

This study evaluated the impacts of α-amylase (AM) and coated α-amylase (CAM) on bull performance, nutrient digestibility, and ruminal fermentation. This study randomized 60 Holstein bulls of 365 ± 11.5 days of age and 457.5 ± 9.35 kg body weight into three groups: without AM addition, adding AM 0.6 g/kg dry matter (DM), and adding CAM 0.6 g AM/kg DM, separately. This whole experimental period was 80 days, including a 20-day adaptation period and a 60-day data and sample acquisition period. In comparison with the unsupplemented control, dry matter intake (DMI) was unaltered; however, average daily gain (ADG) and feed efficiency (FE) were greater for AM or CAM addition. Bulls receiving AM or CAM supply had greater total-tract nutrient digestibility, ruminal total volatile fatty acids (VFA) content, propionate molar proportion, cellulolytic enzyme and AM activities, and the number of microorganisms. In addition, the activities of AM and trypsin in the jejunum and ileum and glucose, albumin, and total protein concentrations in serum were greater for AM or CAM addition compared to the control. When comparing the supplementation mode of AM, bulls receiving CAM addition had greater ADG and FE. The crude protein and starch digestibility and intestinal AM and trypsin activity were higher, while acid detergent fiber (ADF) digestibility was lower for CAM addition than for AM addition. The lower propionate molar proportion and cellobiase and carboxymethyl cellulase activities, together with Ruminococcus albus, Ruminococcus flavefaciens, and Fibrobacter succinogenes populations were observed for CAM addition compared with AM addition. However, there were greater glucose, albumin, and total protein concentrations in serum after adding CAM. According to the data, the supply of AM improved ADG, nutrient digestion, and rumen fermentation. Notably, the optimum supplementation mode was in the form of CAM in bulls.

This experiment was to evaluate the influence of sodium butyrate (SB) addition on milk production, ruminal fermentation, nutrient digestion, and the development and metabolism regulation of the mammary gland in dairy cows. Forty Holstein dairy cows averaging 710 ± 18.5 kg body weight, 72.8 ± 3.66 d in milk (DIM), and 41.4 ± 1.42 kg/d milk production were divided into four treatments blocked by DIM and milk production. Treatments were control group, low SB, medium SB, and high SB with 0, 100, 200 and 300 g/d of SB addition per cow, respectively. The study lasted for 105 d. Production of milk, milk protein and lactose quadratically increased (P < 0.05), while fat-corrected milk, energy-corrected milk and milk fat yields linearly increased (P < 0.05) with increasing SB addition. The digestibility of dietary dry matter, organic matter, and crude protein linearly increased (P < 0.05), whereas the digestibility of ether extract, neutral detergent fibre, and acid detergent fibre quadratically increased (P < 0.05). Ruminal pH quadratically decreased (P = 0.04), while total volatile fatty acids (VFA) quadratically increased (P = 0.03) with increasing SB addition. The acetic acid to propionic acid ratio increased (P = 0.03) linearly due to the unaltered acetic acid molar percentage and a linear decrease in propionic acid molar percentage. Ruminal enzymatic activity of carboxymethyl-cellulase and α-amylase, populations of total bacteria, total anaerobic fungi, total protozoa, Ruminococcus albus, R. flavefaciens, Butyrivibrio fibrisolvens, Fibrobacter succinogenes, and Ruminobacter amylophilus linearly increased (P < 0.05). Blood glucose, urea nitrogen, and non-esterified fatty acids linearly decreased (P < 0.05), while total protein concentration linearly increased (P = 0.04). Moreover, the addition of SB at 200 g/d promoted (P < 0.05) mRNA and protein expression of PPARγ, SREBF1, ACACA, FASN, SCD, CCNA2, CCND1, PCNA, Bcl-2, GPR41, and the ratios of p-Akt/Akt and p-mTOR/mTOR, but decreased (P < 0.05) mRNA and protein expressions of Bax, caspase-3, and caspase-9. The results suggest that milk production and milk fat synthesis increased with SB addition by stimulating rumen fermentation, nutrient digestion, gene and protein expressions concerned with milk fat synthesis and mammary gland development.

Commercial raw or minimally-processed diets, often referred to holistically as raw meat-based diets (RMBD) represent a small portion of the pet food market, but the growth of this sector has been significant in recent years. While traditionally, high-moisture, frozen options were the standard format of commercially available raw diets, freeze-dried raw diets have become more prevalent as of late. Despite the increasing popularity of these commercial raw diet formats, there is a dearth of literature describing their nutritional properties, particularly regarding freeze-dried diets. Therefore, the objective of this experiment was to determine and compare the standardized amino acid (AA) digestibilities and nitrogen-corrected true metabolizable energy (TMEn) of raw frozen and freeze-dried dog foods using precision-fed cecectomized and conventional rooster assays. Three formats of frozen or freeze-dried raw diets provided by Primal Pet Foods (Fairfield, CA, USA) were tested: traditional freeze-dried nuggets (T-FDN), hybrid freeze-dried nuggets (H-FDN), and frozen nuggets (FZN). Diets were fed to cecectomized roosters (4 roosters/diet) to determine AA digestibilities, while conventional roosters (4 roosters/diet) were used to determine TMEn. In both cases, after 26 h of feed withdrawal, roosters were tube-fed 12 to 13 g of test diets and 12 to 13 g of corn. 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 the Mixed Models procedure of SAS version 9.4. There were no significant differences in standardized AA digestibilities among diets, with digestibilities being high for all diets tested. For most of the indispensable AA, digestibilities were greater than or equal to 90% for all diets. Histidine and lysine were the exceptions, with digestibilities ranging from 82% to 87% and 87% to 92%, respectively. Moreover, the reactive lysine:total lysine ratio, a measure of heat damage, ranged from 0.91 to 0.95. TMEn values were higher (P = 0.0127) in T-FDN (6.1 kcal/g) and FZN (5.9 kcal/g) than H-FDN (5.3 kcal/g) and were most similar to those estimated by Atwater factors. In general, all diets tested had high AA digestibilities and had TMEn values that were most similar to Atwater factors.
Commercial raw or minimally-processed diets represent a small portion of the pet food market, but the growth of this sector has been significant in recent years. Despite the increasing popularity of commercial frozen and freeze-dried raw diet formats, there is a dearth of literature describing their nutritional properties. The objective of this experiment was to determine the standardized amino acid (AA) digestibilities and nitrogen-corrected true metabolizable energy (TMEn) of raw frozen and freeze-dried dog foods using precision-fed cecectomized and conventional rooster assays. Diets tested included traditional freeze-dried nuggets (T-FDN), frozen nuggets (FZN), and hybrid freeze-dried nuggets (H-FDN). Diets were fed to cecectomized roosters to determine AA digestibilities, while conventional roosters were used to determine TMEn. In both cases, fasted roosters were tube-fed test diets, and excreta was collected. Standardized AA digestibilities were high for all AA (>90% for most indispensable AA) and were not different among diets. The reactive lysine: total lysine ratio, a measure of heat damage, ranged from 0.91 to 0.95. TMEn values were higher in T-FDN (6.1 kcal/g) and FZN (5.9 kcal/g) than H-FDN (5.3 kcal/g). In general, all diets tested had high AA digestibilities and had acceptable reactive lysine:total lysine ratios.

OBJECTIVE: This study was conducted to investigate the effects of rumen-protected biotin (RPB) on growth performance, nutrient digestibility, nitrogen utilization and plasma biochemical parameters of Liaoning cashmere goats during the cashmere fiber growing period.
METHODS: Sixteen 6-month-old Liaoning cashmere twin-doelings (24.8±1.20 kg) were allocated to 2 diet groups that were individually ad libitum fed 30% concentrate and 70% forage diet (dry matter [DM]) by a paired experimental design. Goats of the control group were fed the basal diet, while goats belonging to the RPB group were fed the basal diet with 10 mg RPB/d per animal. The duration of the experiment was 16 weeks with two 8-week periods. Digestibility was determined at weeks 7 and 15, and other measures were taken every four weeks.
RESULTS: Compared with the control group, the average daily gain of the RPB group increased by 10.94% (p<0.05), and the intake of neutral detergent fiber was increased (p = 0.045). There were some increasing tendencies for the intake of DM, acid detergent fiber and ether extract (p = 0.070, 0.088, and 0.070, respectively). The intake and digestibility of N tended to increase (p = 0.062 and 0.093, respectively), while the N fecal excretion percentage of N intake was decreased (p = 0.093) in the RPB compared with the control group. N retention tended to increase (p = 0.084) with the addition of adding RPB to the diet. Plasma total protein was increased (p = 0.037), whereas the urea-N concentration was decreased (p = 0.049) in the RPB diet group compared with the control diet group. The levels of propionyl-CoA carboxylase (p<0.001) and methylmalonyl-CoA (p = 0.013) were increased in the RPB group.
CONCLUSIONS: Supplementation of rumen-protected biotin in the diet of cashmere goats can enhance the utilization of N and improve daily weight gain during cashmere fiber growing period.

The ongoing use of plastic polymers to manufacture food packaging has raised concerns about the presence of nano- and microplastics (NMPs) in a variety of foods. This review provides the most recent data on NMPs\' migration from plastic packaging into dairy products. Also discussed are the possible effects of NMPs on nutrient digestion, absorption, and metabolism. Different kinds of dairy products, including skimmed milk, whole liquid milk, powder milk, and infant formula milk, have been found to contain NMPs of various sizes, shapes, and concentrations. NMPs may interact with proteins, carbohydrates, and fats and have a detrimental impact on how well these nutrients are digested and absorbed by the body. The presence of NMPs in the gastrointestinal tract may impact how lipids, proteins, glucose, iron, and energy are metabolized, increasing the risk of developing various health conditions. In addition to NMPs, plastic oligomers released from food packaging material have been found to migrate to various foods and food simulants, though information regarding their effect on human health is limited. Viewpoints on potential directions for future studies on NMPs and their impact on nutrient digestion, absorption, and health are also presented in this review.

Using single-cell-based proteins in pet foods is of interest, but little testing has been done. Therefore, our objective was to determine the amino acid (AA) digestibilities, assess protein quality of a novel microbial protein (MP) (FeedKind), and compare it with other protein-based ingredients using the precision-fed cecectomized rooster assay. Test ingredients included: MP, chicken meal (CM), corn gluten meal (CGM), pea protein (PP), and black soldier fly larvae. Thirty cecectomized roosters (n = 6/ingredient) were randomly assigned to test ingredients. After 24 h of feed withdrawal, roosters were tube-fed 15 g test ingredient and 15 g corn, and then excreta were collected for 48 h. Endogenous AA corrections were made using additional roosters. Digestible indispensable AA score (DIAAS)-like values were calculated to determine protein quality according to Association of American Feed Control Officials (AAFCO), The European Pet Food Industry Federation, and National Research Council reference values for growing and adult dogs and cats. Data were analyzed using the Mixed Models procedure of SAS 9.4, with P ≤ 0.05 being significant. All reactive lysine:total lysine ratios, an indicator of heat damage, were higher than 0.9, except for CM (0.86). Digestibility of indispensable and dispensable AA were >85% and >80% for MP, respectively, with indispensable AA digestibilities being >80% for all other ingredients. In general, CGM had the highest, while CM had the lowest AA digestibilities. Two exceptions were lysine and tryptophan. Lysine digestibility for MP was higher than that of all other ingredients, while tryptophan digestibility for MP was higher than that of CM, CGM, and PP. Threonine digestibility was highest for CGM and MP. Valine digestibility was highest for CGM, PP, and MP. DIAAS-like calculations identified limiting AA of each ingredient and depended on the reference used and life stage and species of animal. Using AAFCO guidelines, all DIAAS-like values for MP were >100 suggesting that it could be used as the sole source of protein in adult dog and cat diets; only methionine had DIAAS-like values <100 for growing kittens. For dogs, limiting AA was most commonly methionine, threonine, and tryptophan in the other protein sources. For cats, limiting AA was most commonly lysine and methionine. Lysine was severely limited in CGM across all life stages considered. Further research in dogs and cats is necessary, but our data suggest that the MP tested has high AA digestibilities and is a high-quality protein source that may be useful in pet foods.
Single-cell-based proteins are of interest for use in pet foods, but little testing has been done. The objective of this experiment was to compare the amino acid (AA) digestibilities and protein quality of a novel microbial protein (MP) (FeedKind) with chicken meal (CM), corn gluten meal (CGM), pea protein (PP), and black soldier fly larvae ingredients using the precision-fed cecectomized rooster assay. Cecectomized roosters were tube-fed the test ingredients and excreta were collected. All reactive lysine:total lysine ratios, an indicator of heat damage, were higher than 0.9, except for CM. Digestibility of indispensable and dispensable AA were >85% and >80% for MP, respectively, with indispensable AA digestibilities being >80% for all other ingredients. In general, CGM had the highest, while CM had the lowest AA digestibilities. Lysine and tryptophan were exceptions, being highest for MP. Threonine and valine digestibilities were also high for MP. Digestible indispensable AA score-like values identified limiting AA of each ingredient. Limiting AA was most commonly methionine, threonine, and tryptophan for dogs and lysine and methionine for cats. Our data suggest that the MP tested has high AA digestibilities and is a high-quality protein source that may be useful in pet foods.

Vegan, mildly cooked, and human-grade dog foods are becoming more popular, as beliefs and views of pet owners change. To our knowledge, however, dog studies have not examined the digestibility of commercial vegan diets. Therefore, the objective of this study was to determine the apparent total tract digestibility (ATTD) of mildly cooked human-grade vegan dog foods and their effects on blood metabolites and fecal microbiota, characteristics, and metabolites of adult dogs consuming them. Three commercial dog foods were tested. Two were mildly cooked human-grade vegan dog diets, while the third was a chicken-based extruded dog diet. Twelve healthy adult female beagles (7.81 ± 0.65 kg; 7.73 ± 1.65 yr) were used in a replicated 3 × 3 Latin Square design. The study consisted of three experimental periods, with each composed of a 7 d diet adaptation phase, 15 d of consuming 100% of the diet, a 5 d phase for fecal collection for ATTD measurement, and 1 d for blood collection for serum chemistry and hematology. During the fecal collection period, a fresh sample was collected for fecal scoring and dry matter, pH, metabolite, and microbiota measurements. All data were analyzed using the Mixed Models procedure of SAS (version 9.4). All three diets were shown to be highly digestible, with all macronutrients having digestibility values above 80%. The vegan diets had higher (P < 0.001) ATTD of fat, but lower (P < 0.05) ATTD of organic matter than the extruded diet. Dogs consuming the vegan diets had lower circulating cholesterol (P < 0.001), triglyceride (P < 0.001), and platelet (P < 0.009) concentrations and lower (P < 0.010) blood neutrophil percentages than dogs consuming the extruded diet. Dogs consuming vegan diets had lower (P < 0.001) fecal dry matter percentages, lower (P < 0.001) fecal phenol and indole concentrations, and higher (P = 0.05) fecal short-chain fatty acid concentrations than those consuming the extruded diet. Fecal bacterial alpha and beta diversities were not different (P > 0.05) among diets, but dogs consuming vegan diets had altered (P < 0.05) relative abundances of nearly 20 bacterial genera when compared with those consuming the extruded diet. In conclusion, the mildly cooked human-grade vegan dog foods tested in this study performed well, resulting in desirable fecal characteristics, ATTD, and serum chemistries. The vegan diets tested also led to positive changes to serum lipids and fecal metabolites, and interesting changes to the fecal microbial community.
Vegan, mildly cooked, and human-grade dog foods are increasing in popularity, but few studies have been performed to examine their performance. Our objective was to determine the apparent total tract digestibility (ATTD) of mildly cooked human-grade vegan dog foods and their effects on blood metabolites and fecal microbiota, characteristics, and metabolites of dogs. Two mildly cooked human-grade vegan dog diets and a chicken-based extruded dog diet were tested using 12 healthy adult dogs in a replicated 3 × 3 Latin Square design. All diets were highly digestible, with all macronutrients having digestibility values >80%. Vegan diets had higher ATTD of fat, but lower ATTD of organic matter than the extruded diet. Dogs consuming vegan diets had lower circulating cholesterol, triglycerides, platelets, and neutrophils than dogs consuming the extruded diet. Dogs consuming vegan diets had lower fecal dry matter percentages and phenol and indole concentrations, and higher fecal short-chain fatty acid concentrations than those consuming the extruded diet. Finally, ~20 bacterial genera were altered between dogs consuming vegan and extruded diets. In conclusion, the mildly cooked human-grade vegan dog foods tested performed well, resulting in desirable fecal characteristics, high ATTD, adequate serum chemistries, positive changes to serum lipids and fecal metabolites, and interesting changes to fecal microbiota.