Effects Of Dietary Betaine Research Articles

Effect of Dietary Betaine, Glycine, and Choline Supplementation on Productive Performance, Egg Quality, Immune Response, and Serum Measurement of Aged Laying Hens Raised under Heat Stress Conditions

Effect of Dietary Betaine, Glycine, and Choline Supplementation on Productive Performance, Egg Quality, Immune Response, and Serum Measurement of Aged Laying Hens Raised under Heat Stress Conditions

Effects of Dietary Betaine on the Laying Performance, Antioxidant Capacity, and Uterus and Ovary Function of Laying Hens at the Late Stage of Production.

Betaine has been found to alleviate oxidative stress, inflammation, and apoptosis. However, whether dietary betaine can protect late-laying hens against these adverse effects is unknown. Here, 270 65-week-old Jinghong-1 laying hens were randomly divided into the Control, 0.1% Betaine, and 0.5% Betaine groups and fed a basal diet, 0.1%, and 0.5% betaine supplemented diet, respectively. The trial lasted for seven weeks. Birds that consumed 0.5% betaine laid more eggs with thicker eggshells. Accordingly, uterine reduced glutathione (GSH), glutathione peroxidase (GSH-PX), and ovarian superoxide dismutase (SOD) contents were increased. The uterine calcium ion content and the mRNA expression of ovalbumin, ovotransferrin, and carbonic anhydrase two were increased. Moreover, ovarian IL-1β, Caspase-1, Caspase-8, and Caspase-9 mRNA expressions were decreased; luteinising hormone receptor (LHR) and follicle-stimulating hormone receptor mRNA expressions were increased. Furthermore, dietary betaine decreased the ovaries' mRNA expression of DNA methyltransferase 1 (DNMT)1, DNMT3a, and DNMT3b. The methylation level at the promoter region of ovarian LHR decreased. These results indicated that dietary betaine consumption with a concentration of 0.5% could increase the laying rate and the eggshell thickness during the late-laying period. The underlying mechanism may include antioxidative, anti-apoptosis, and hormone-sensitivity-enhancing properties.

Effects of dietary betaine and protected calcium butyrate supplementation on growth performance, blood biochemical status, and meat quality in growing Japanese quail (Coturnix coturnix Japonica).

This study aimed to evaluate the impact of betaine (Bet) and protected calcium butyrate (PCB) supplementation individually and together on the performance, carcass traits, blood biochemistry, and meat quality of growing Japanese quails ( Coturnix coturnix Japonica) from 1 to 42 days old. 144 one-day-old unsexed Japanese quails were randomly assigned to four dietary treatments with six replicates each. All birds were fed a maize-soybean meal diet for 42 days. The control group received no feed additives, while the treatment groups received 1.2 g/kg Bet, 1.0 g/kg PCB, or a combination of both in their diets. The results indicated that Bet and PCB supplementation individually and together did not differ performance, relative weights of heart, gizzard, proventriculus, bursa of Fabricius and pancreas, water holding capacity (WHC), cooking loss (CL), blood biochemical values except for glucose and triglyceride. Bet supplementation significantly increased relative liver weights, while PCB supplementation decreased glucose levels in serum. Moreover, carcass yield was increased and triglyceride value in blood serum, malondialdehyde (MDA), and the pH levels of breast meats both on the 1st and 30st day of post-mortem were decreased in all treatment groups. Therefore, based on these results, the combination of betaine and butyrate improves both carcass yield and meat quality in growing Japanese quails. More research is needed to determine the impact of betaine and butyrate on the structure of amino acids in meat, antioxidant enzyme activity, and the immune system in poultry.

Effect of Dietary Betaine on Oxidative Stress and Immune Response in Postpartum Lactating Murrah Buffaloes (Bubalus bubalis) during Hot-Humid Season

Effect of Dietary Betaine on Oxidative Stress and Immune Response in Postpartum Lactating Murrah Buffaloes (Bubalus bubalis) during Hot-Humid Season

Effect of dietary betaine on endocrine profile in postpartum lactating Murrah buffaloes during hot-humid season

Extreme heat along with metabolic stress associated with the postpartum period negatively affects the endocrine status of animals. Betaine is a feed additive that promotes animal growth. Since betaine contains three methyl groups, it acts as a methyl donor in animal metabolism. Eighteen postpartum Murrah buffaloes were randomly divided into T1 Group (Control), T2 and T3 Group was supplemented with betaine 50 g/animal/day and 100 g/animal/day respectively from 5th day postpartum and was continued up to 4 months postpartum. On day 50 postpartum the mean value of plasma cortisol of T1 Group was maximum followed by T2 Group and T3 Group had minimum plasma cortisol mean value which differed (P<0.05) significantly between groups. The mean concentration of plasma T3 total, T4 total, progesterone and estrogen showed (P>0.05) non-significant difference between all the groups. However, betaine fed T2 and T3 Group had higher plasma T3, T4, progesterone and estrogen as compared to control, it might be due to the effect of betaine, which reduces metabolic stress and activate hypothalmo-pituitary and gonadal axis after parturition and lactation period during heat stress.

O169 Exposure of Iberian pigs to heat: effects of dietary betaine and zinc on heat production

O169 Exposure of Iberian pigs to heat: effects of dietary betaine and zinc on heat production

Effects of dietary betaine on body temperature indices, performance, metabolism, and hematological variables of dairy heifer calves during hot summer conditions.

Background and Aim:Heat stress (HS) can negatively impact farm animal productivity and adversely affect animal welfare worldwide, placing a major financial burden on global livestock producers. Dietary betaine (trimethylglycine) has been known to have several biological functions, which may aid in offering beneficial effects on livestock productivity during HS conditions. However, information on the role of dietary betaine in heat-stressed dairy heifer calves is yet to be documented. Therefore, this study aimed to assess the effects of supplementing dietary betaine on body temperature indices, blood metabolites, productive performance, and complete blood count (CBC) (hematological indices) in hyperthermic dairy heifer calves.Materials and Methods:In total, 14 Holstein heifer calves (4.0 ± 0.9 months old) were individually housed and randomly allocated to one of two dietary treatments: (1) a control diet (CON; n = 7) and (2) a control diet complemented with 21 g/d of natural betaine (BET; n = 7) top-dressed once daily. The experiment lasted for 28 d, during which all animals were subjected to natural cyclic HS conditions (26.1–39.2°C; 73.2–84.0 temperature–humidity index). Rectal temperature (RT) and respiration rate (RR) were measured twice daily (0700 and 1500 h), whereas dry matter intake (DMI) was measured once daily (0800 h). In addition, blood samples (collected from the jugular vein) were analyzed for metabolites and CBC on days 7, 14, 21, and 28.Results:Relative to CON, BET supplementation was able to decrease RT on day 23 of the experiment (p = 0.04). Alternatively, RR was similar between the dietary treatments (p = 0.73). Feeding BET did not affect DMI compared with CON during HS conditions (p = 0.48). Furthermore, compared with CON, BET supplementation did not change leukocytes, neutrophils, lymphocytes, and hematocrit levels during HS conditions (p ≥ 0.17). However, a post hoc analysis indicated that hematocrit levels were decreased in BET-fed calves on day 7 of the study compared with CON calves during HS conditions (p = 0.05). Moreover, circulating glucose, albumin, and triglycerides were found to be similar between dietary treatments (p ≥ 0.55).Conclusion:BET supplementation slightly reduced RT and circulating hematocrit but did not affect other metrics in this HS experiment. More research into the effects of different doses of dietary BET on dairy heifer calves is needed.

Exposure of growing Iberian pigs to heat stress and effects of dietary betaine and zinc on heat tolerance

The effects of heat stress and dietary betaine and zinc on growth, weight of organs and plasma biochemistry in growing Iberian pigs are of special importance. Forty Iberian barrows (43.8 kg BW) were assigned to five treatments for 28-d: 1.-thermoneutral (20 °C)-ad libitum fed a control diet (TN-CON); 2.-heat stress (30 °C)-ad libitum fed a control diet (HS–CON); 3.-thermoneutral-pair-fed a control diet (TN–CON–PF) on the basis of intake of HS-CON; 4.-heat stress-ad libitum fed a betaine-supplemented diet (HS-BET); 5.-heat stress-ad libitum fed a zinc-supplemented diet (HS-ZN).Heat stress increased rectal temperature and decreased feed intake. As a result, weight gain under TN-CON was greater than under heat stress or TN–CON–PF. Temperature did not affect gain to feed ratio. Heat stress decreased empty BW, kidneys and spleen weights, and tended to decrease total viscera weight compared to thermoneutral counterparts fed ad libitum, but when organ weight was related to empty BW, only spleen tended to decrease. At identical intake, heat stress tended to decrease heart weight. Betaine and zinc had no effect on organs weight under heat stress. Heat stress decreased albumin and the homeostasis model assessment index for estimating β-cell function (HOMA-%B), increased glucose, and tended to increase urea compared with the TN pair-fed group. Betaine and zinc decreased plasma glucose under heat stress and increased HOMA-%B suggesting improved β-cell function. Insulin, quantitative insulin sensitivity check index, homeostasis model assessment index for estimating insulin resistance percentage and the rest of biochemical parameters were not affected by treatments. Decreased intake explained the consistent negative effects on performance of pigs after long-term heat stress. Furthermore, it elicited a glucose sparing effect without affecting insulin concentration and increased protein catabolism. Betaine or zinc supplementation did not prevent the negative effect of heat stress on growth performance of Iberian pigs.

Effect of Dietary Betaine on Muscle Protein Deposition, Nucleic Acid and Amino Acid Contents, and Proteomes of Broilers.

Simple SummaryIn animal production, growth trials have shown that betaine has a positive effect on growth performance, especially improving meat yield. Proteins are the largest unit comprising muscle cells except moisture. However, how betaine regulates muscle protein anabolism and abundance levels remains unclear. Therefore, this study was conducted to investigate the effect of dietary betaine on growth performance, muscle protein deposition, and proteome of broilers. The results suggested that betaine could improve growth performance and muscle protein deposition of broilers. Alterations in muscle nucleic acids, amino acids, and protein abundance levels were involved in this process. Proteomic analysis further revealed that 35 proteins in breast muscle were identified as differentially abundant proteins by betaine supplementation, which were mainly related to cell differentiation, small molecule metabolic process, and tissue development.To investigate the effect of betaine supplementation on growth performance, muscle protein deposition, muscle nucleic acid and amino acid contents, and muscle proteome of broilers, 160 one-day-old male partridge shank broiler chickens were randomly divided into 2 groups with 8 replicates of 10 broilers each. Broilers were fed a basal diet alone, or a basal diet supplemented with 1000 mg/kg betaine. Compared with the control group, the betaine group significantly increased (p < 0.05) the broilers average daily gain, the levels of serum insulin-like growth factor-1 (IGF-1), growth hormone (GH), total protein (TP), the contents of muscle absolute protein deposition, RNA, Ser, Glu, Met, and Phe, and the ratio of RNA/DNA, and decreased (p < 0.05) the feed conversion ratio and serum blood urea nitrogen content. Moreover, proteomic analysis revealed 35 differentially abundant proteins (DAPs) in the betaine group compared with the control group, including 27 upregulated proteins and 8 downregulated proteins (p < 0.05). These DAPs were mainly related to cell differentiation, small molecule metabolic process, and tissue development. In conclusion, diets supplemented with 1000 mg/kg betaine improved growth performance and muscle protein deposition of broilers. Increased serum GH, IGF-1, and TP contents, and alterations in muscle nucleic acids, amino acids, and protein abundance levels were involved in this process.

Thermotolerance of Broiler Chicks Ingesting Dietary Betaine and/or Creatine.

Simple SummaryImproving broiler performance is still an essential task in animal production, especially under certain environmental challenge conditions. Heat stress is among the first and crucial limiting factors of the development of poultry production in warm regions. Betaine (B) and creatine (C) are seemingly two promising additives that showed enhancement in water metabolism in several animal species. Despite the clear beneficial effect of B and/or C on water metabolism, limited information is available about their use and effect on performance and thermophysiological responses of broiler chicks exposed to heat stress challenge. In view of the above consideration and in order to improve the productivity of broiler chickens, the present study was designed to examine the potential alteration in water metabolism in broiler chicks treated with B and/or C under thermoregulation challenge, which may contribute to the ongoing efforts to improve broiler chicken production. Under the current study conditions, the results demonstrated that performance and carcass parameters measured were not affected by B and/or C supplementation by the end of the rearing period. In light of the improved thermoregulatory performance and water balance indicators, it seems that B and/or C have successfully improved water holding capacity and therefore helped in enhancing thermo-tolerance.The present study aimed to assess the effect of dietary betaine (B) and/or creatine (C) on performance and thermoregulatory responses of broiler chicks. Indian River broiler chicks, fitted with compact thermosensors, were reared to market age (five weeks). The chicks were randomly distributed into four treatment groups, in a 2 × 2 factorial arrangement of treatments—basal control diet (Control group: CONT; B−/C−); 1 g betaine/kg feed (Betaine group: BETA; B+/C−), 1.2 g creatine monohydrate/kg feed (Creatine group: CRET; B−/C+), and combination (Betaine and Creatine group: COMB; B+/C+) of both supplements. At 31 days of age, 20 chicks from each group were exposed to acute heat stress (A-HS) for 3 h (34.45 ± 0.20 °C), and hemogramic profiles were screened before and after. Performance parameters (feed intake, body weight gain, and feed conversion ratio) were reported on a weekly basis, and carcass meat quality was evaluated at the end of experiment. Redness of breast was higher due to B and C treatments separately than the CONT group (B by C interaction; p < 0.05). Compared to the CONT, dietary supplements alleviated hyperthermia responses, with B alone being more efficient than C or COMB treatments. The mitigation of hyperthermia is likely mediated by enhancement of water balance indicators. Although not efficient in improving growth performance, dietary B and/or C are efficient in improving thermophysiological performance and survival of finishing broiler chicks under A-HS.

Effects of Dietary Betaine on Growth Performance, Digestive Function, Carcass Traits, and Meat Quality in Indigenous Yellow-Feathered Broilers under Long-Term Heat Stress

Simple SummaryHeat stress, one of the major problems in tropical and subtropical regions, adversely affects poultry production. This study was designed to evaluate the effects of dietary betaine on growth performance, digestive function, carcass traits, and meat quality in indigenous yellow-feathered broilers subjected to long-term heat stress. The results demonstrated that long-term heat exposure reduced the growth performance, digestive function, and carcass yield, and dietary betaine supplementation partially alleviated the adverse effects of heat stress on these parameters. These findings are useful for development of anti-heat stress feed additives in indigenous yellow-feathered broilers.Heat stress has a profound effect on poultry health and productivity. The present study evaluated whether feeding betaine could ameliorate long-term heat stress-induced impairment of productive performance in indigenous yellow-feathered broilers. A total of 240 five-week-old male broilers were randomly allocated to five treatments with six replicates of eight broilers each. The five treatments included a thermoneutral zone control group (TN, fed basal diet), a heat stress control group (HS, fed basal diet), and an HS control group supplemented 500, 1000, 2000 mg/kg betaine, respectively. The TN group was raised at 26 ± 1 °C during the whole study, HS groups exposed to 32 ± 1 °C for 8 h/day from 9:00 am to 17:00 pm. The results showed that heat stress decreased the body weight gain (BWG) and feed intake of broilers during 1–5, 6–10, and 1–10 weeks (p < 0.05). Dietary betaine tended to improve the BWG and feed intake of broilers under 5 weeks of heat stress (linear, p < 0.10), and betaine supplementation linearly increased the BWG and feed intake during 6–10 and 1–10 weeks (p < 0.05). Additionally, nitrogen retention was reduced by 5 weeks and 10 weeks of heat stress (p < 0.05), whereas dietary betaine could improve nitrogen retention in heat stressed broilers after both 5 and 10 weeks of heat stress (linear, p < 0.05). Moreover, this study observed that the trypsin activity of jejunum was decreased by 5 weeks of heat stress (p < 0.05), whereas betaine supplementation had quadratic effects on trypsin activity of jejunum in heat stressed broilers (p < 0.05). Furthermore, 10 weeks of heat stress induced a reduction of villus height of the duodenum and jejunum (p < 0.05), and decreased the villus height to crypt depth ratio of the jejunum (p < 0.05). Supplementation with betaine ameliorated the adverse effects of heat stress on these parameters (p < 0.05). Compared with the TN group, 10 weeks of heat stress reduced carcass and breast yield (p < 0.05) and betaine supplementation improved carcass and breast yield of heat stressed broilers (linear, p < 0.05). In conclusion, dietary supplementation of betaine could reduce the detrimental effects of long-term heat stress on growth performance, digestive function, and carcass traits in indigenous yellow-feathered broilers.

Effect of dietary betaine and choline association on lipid metabolism in blunt snout bream fed a high‐fat diet

Effect of dietary betaine and choline association on lipid metabolism in blunt snout bream fed a high‐fat diet

Effects of dietary betaine in allogynogenetic gibel carp (Carassius auratus gibelio): Enhanced growth, reduced lipid deposition and depressed lipogenic gene expression

A 10-week feeding experiment was conducted to evaluate the effects of supplemental betaine on growth performance, body composition and lipid deposition in allogynogenetic gibel carp. Four isoproteic (37% crude protein) and isolipidic (5% crude lipid) artificial diets with 0%, 0.08%, 0.4% and 2% betaine supplementation were formulated, and named VB0, VB0.08, VB0.4 and VB2, respectively. Each diet was fed in triplicate to fish about 10 g in weight. The results showed that 0.4% betaine supplementation significantly improved growth performance and reduced lipid content in the hepatopancreas, muscle and the whole body compared with the control group. Moreover, both fatty acid synthase and acetyl-CoA carboxylase, two important lipogenic genes, showed significantly lower expression in the VB0.4 group than in the control group, and a strong correlation was detected between lipid content and mRNA expression levels for FAS and ACC in the hepatopancreas. Taken together, appropriate (0.4%) betaine supplementation in the diet not only improved growth, but also reduced lipid deposition in allogynogenetic gibel carp, probably by diminishing lipogenic gene expression.

Effect of Dietary Betaine on Metabolic Syndrome Risk Factors in Asian

Objective: Betaine (trimethylglycine) is a naturally-occurring osmolyte and methyl donor with reported effects on liver metabolism. The aim of this study was to evaluate the safety and the effects of betaine administration to metabolic risk factors in Asian males. Methodology: Twenty Japanese males (30-59 years) with mild fatty liver were enrolled in this blinded, placebocontrolled, randomized, parallel trial to assess the effects of 3 g of daily betaine for 12 weeks on safety and metabolic biomarkers. Selection criteria included fatty liver disease, as assessed by an abdominal ultrasonogram (US), the practice of moderate alcohol consumption, liver performance status and body mass index (≤27). Abdominal computed tomography (CT) as well as blood and urine sampling were performed before and after the intervention period. Results: No differences in the degree of hepatic steatosis or in the occurrence of adverse events were observed between the groups. Compared to the placebo group, the betaine group showed a significant increase in plasma betaine (P<0.0001) and high-density lipoprotein (HDL)-cholesterol (P<0.05) concentrations. Conclusion: Low-dose betaine supplementation to subjects with mild fatty liver disease is safe and well tolerated. Betaine increased plasma HDL which may reflect the favorable effects of betaine on liver function-related metabolic metabolism in Asian population.

Effect of dietary betaine on short chain fatty acid and blood profile in meat duck exposed to extreme heat stress

Effect of dietary betaine on short chain fatty acid and blood profile in meat duck exposed to extreme heat stress

Effects of dietary betaine on growth performance, fat deposition and serum lipids in broilers subjected to chronic heat stress.

We evaluated the effects of supplementing betaine on growth performance, fat deposition and lipid metabolism status in broilers kept under chronic heat stress. Five hundred and forty chicks were randomly divided into six groups and the two normal temperature groups were held at normal ambient temperature and fed the basal diet (CONT) and basal diet plus 0.1% betaine, respectively. Heat stressed (HS) broilers were held at 32 ± 1°C from days 22 to 42 and fed the basal diet containing variable levels of betaine. Broilers were examined at days 28, 35 and 42 for body weight, feed consumption, fat deposition and serum lipids. The CONT and betaine-supplemented groups showed higher (P < 0.01 or P < 0.05) feed consumption, body weight gain, and lower feed : gain ratio compared with the HS-CONT group. Meanwhile, heat stress increased abdominal, intermuscular and subcutaneous fat deposition, whereas the supplemental betaine significantly decreased those compared with the HS-CONT group. Additionally, betaine supplementation significantly decreased triglyceride, free fatty acids, low-density lipoprotein cholesterol and high-density lipoprotein cholesterol compared with HS-CONT. Chronic HS reduces broiler production performance. However, betaine can reverse these negative effects partially and thus improve carcass composition by changing lipid metabolism.

Effects of dietary betaine on milk yield and milk composition of mid-lactation Holstein dairy cows

Betaine, naturally found in plants and an oxidative product of choline, is converted to acetate in the rumen, which may be used for milk fat synthesis. The objective of this study was to determine the effect of supplemental dietary betaine on milk yield and milk composition. Eighteen Holstein dairy cows (126±5 d in milk; mean ± SD) were randomly assigned to a sequence of treatments of rumen-unprotected betaine at 0, 25, 50, and 100g/d added to a standard lactation ration in a 4×4 Latin square design. Animals were fed individually with feed intake and milk yield recorded daily. Body condition score and body weight were recorded on the last day of each period that lasted 16 d, with milk sampled on the last 2d of each period. Milk composition was determined by a Dairy Herd Improvement Association laboratory and milk fatty acids were determined by gas chromatography. Data collected over the last 2 to 3d were analyzed using the MIXED procedure in SAS (SAS Institute Inc., Cary, NC). Milk yield (mean ± SEM) was increased by betaine when fed at 100g/d (22.4, 22.5, 22.8, 24.1±1.19kg/d for 0, 25, 50, and 100g of betaine/d, respectively). No effect of dietary betaine was detected on dry matter intake, feed efficiency, body weight, or body condition score. Percentages of milk fat, lactose, solids-not-fat, and somatic cell count were not altered; however, protein concentration was decreased by betaine supplementation as compared with the control (3.35, 3.28, 3.27, and 3.28±0.07% for 0, 25, 50, and 100g of betaine/d, respectively). Daily yields of milk protein, fat, lactose, energy-corrected milk, and 3.5% fat-corrected milk did not differ with betaine supplementation. Overall, inclusion of dietary betaine at 100g/d increased milk yield, whereas all levels of betaine supplementation decreased milk protein percent and slightly altered milk fatty acid profile. Further studies are needed to determine the ruminal fermentation characteristics and the optimum rate of supplemental betaine for dairy cows.

Effect of Dietary Betaine on Performance, Immunocompetence and Gut Contents Osmolarity of Broilers Challenged With a Mixed Coccidial Infection

Effect of Dietary Betaine on Performance, Immunocompetence and Gut Contents Osmolarity of Broilers Challenged With a Mixed Coccidial Infection

Dietary Betaine Affect Duodenal Histology of Broilers Challenged with a Mixed Coccidial Infection

The purpose of this research was to investigate effect of dietary betaine on intestinal morphology after an experimental coccidiosis. Hence a total of 189 male and female broiler chicks were randomly assigned to 9 floor cages. Chicks were fed a basal diet supplemented with 0, 0.6 or 1.2 g kg(-1) betaine. All birds were inoculated orally with Eimeria oocysts on day 28. Duodenal morphology parameters and lesions were scored by microscopic observation on intestine samples which were taken at day 42 of age. Adding 1.2 g kg(-1) betaine to diet diminished intestinal lesions (p < 0.05). Dietary supplementation with 0.6 or 1.2 g kg(-1) betaine significantly (p < 0.01) increased intraepithelial lymphocytes as well. Level of additive betaine had no effect on the ratio of villus height/crypt depth or villus surface area. Lamina propria of duodenum became thicker in the intestine of chickens which received more supplemental betaine via their diet. In conclusion, since the number of intraepithelial lymphocytes and thickness of lamina propria represent the condition of gut immune response, it seems that dietary betaine may immunomodulate the gastrointestinal tract of broilers. In addition, betaine effect on villus morphology measured later in life differed from what had been measured already earlier in life of the chicks.

Intestinal effects of dietary betaine in piglets.

The study was conducted to investigate the effects of graded dietary inclusion levels of betaine on ileal and total tract nutrient digestibilities and intestinal bacterial fermentation characteristics in piglets. A total of 8 barrows (BW 7.9 kg) was fitted with simple T-cannulas at the distal ileum. The animals were randomly allocated to 1 of the 4 assay diets with 2 pigs per treatment in 4 repeated measurement periods. The assay diets included a basal diet based on wheat, barley and soybean meal alone, or supplemented with a liquid betaine product at dietary levels of 1.5, 3.0, or 6.0 g betaine kg–1 diet (as–fed). Ileal digestibilities of dry matter (DM) and neutral detergent fiber (NDF) increased both quadratically and linearly (P<0.05), and ileal digestibility of glycine increased linearly as dietary betaine level increased (P<0.05). Moreover, there were linear increases in the concentrations of ileal D–lactic acid (P<0.05), indicating intensified intestinal bacterial activities as dietary betaine level increased. At the fecal level, total tract crude protein (CP) digestibility increased quadratically (P<0.05), and digestibility of amino acids (AA) tended to increase quadratically (P=0.06 to P=0.11), except for proline (P>0.05), as dietary betaine level increased. The increased bacterial degradation of CP and AA in the large intestine coincides with the linear increase (P<0.05) in fecal diaminopimelic acid concentrations, indicating enhanced intestinal bacterial growth with increasing dietary betaine levels. In most cases, there was a response in the variables that were measured up to 3.0 g betaine per kg diet, whereas increasing the betaine level from 3.0 to 6.0 g betaine per kg diet had no additional effect. It can be concluded that dietary betaine stimulates microbial fermentation of fiber in the small intestine, leaving less fermentable fiber to reach the large intestine and therefore, increased microbial degradation of protein in the large intestine may occur. Keywords: piglets, betaine, digestibility, bacterial fermentation, microflora