Diet Acidification Research Articles

Acidified diet is not effective in preventing hypocalcemia in dairy cows on French commercial farms

The objective of this study was to assess, in the context of typical dairy farms in western France, the preventive effects of prepartum diet acidification (AcD) and mineral intake during late gestation on the incidence of subclinical hypocalcemia (SHC) and subclinical hypophosphatemia (SHP) after calving. We conducted a longitudinal study that followed a cohort of 371 Holstein cows from 26 French dairy farms; of these, 235 cows (15 farms) were supplied with anionic salts during late gestation, and 136 cows (11 farms) were not. Blood samples were collected from 1 to 22 cows per farm (average of 14.3 cows per farm) between 24 and 48 h after calving. Total calcium and inorganic phosphorus concentrations in plasma were then quantified by inductively coupled plasma - optical emission spectrometry. The effects of AcD on the incidence of SHC and SHP were assessed using mixed linear models that evaluated the cow-level factors parity, milk yield index, and individual health events/treatments, and the farm-level factors diet calcium and magnesium content, dietary phosphorus intake, vitamin D supply, diet crude protein content, and duration of AcD, with farm as a random effect. Approximately 55% of cows were diagnosed with SHC (calcium < 2.0 mmol/l, n = 203) and 37% with SHP (inorganic phosphorus < 1.3 mmol/l, n=136). The first model confirmed earlier findings that the risk of SHC is higher with increased parity (P ≤ 0.0001) and revealed a higher risk associated with high milk yield (P = 0.0005), high phosphorus intake (40–60 g/cow per day, OR = 3.5; ≥ 60 g/cow per day, OR = 7.3; P = 0.0003) and high vitamin D supply (≥ 19950 IU/cow per day, OR = 3, P = 0.007). The second model highlighted a greater risk of SHP with increasing parity (P = 0.03) and showed trends for the preventive effects of AcD (OR = 0.4, P = 0.07) and moderate amounts of phosphorus in the diet (OR = 0.4, P = 0.10). Overall, our results do not support the effectiveness of AcD in preventing SHC or SHP under field conditions examined here, probably resulting from insufficient diet acidification.

Acidification of drinking water improved tibia mass of broilers through the alterations of intestinal barrier and microbiota.

ObjectiveDiet acidification supplementation is known to influence intestinal morphology, gut microbiota, and on phosphorus (P) utilization of broilers. Alterations in intestinal barrier and microbiota have been associated with systemic inflammation and thus regulating bone turnover. Hence the effect of acidifier addition to drinking water on tibia mass and the linkages between intestinal integrity and bone were studied.MethodsOne-d-old male broilers were randomly assigned to normal water (control) or continuous supply of acidified water (2% the blend of 2-hydroxy-4-methylthiobutyric acid, lactic, and phosphoric acid) group with 5 replicates of 10 chicks per replicate for 42 d.ResultsAcidification of drinking water improved the ash percentage and calcium content of tibia at 42 d. Broilers receiving acidified water had increased serum P concentration compared to control birds. The acidified group showed improved intestinal barrier, evidenced by increased wall thickness, villus height, the villus height to crypt depth ratio, and upregulated mucin-2 expression in ileum. Broilers receiving drinking water containing mixed organic acids had a higher proportion of Firmicutes and the ratio of Firmicutes and Bacteroidetes, as well as a lower population of Proteobacteria. Meanwhile, the addition of acidifier to drinking water resulted in declined ileal and serum proinflammatory factors level and increased immunoglobulin concentrations in serum. Concerning bone remodeling, acidifier addition was linked to a decrease in serum C-terminal cross-linked telopeptide of type I collagen and tartrate-resistant acid phosphatase reflecting bone resorption, whereas it did not apparently change serum alkaline phosphatase activity that is a bone formation marker.ConclusionAcidified drinking water increased tibia mineral deposition of broilers, which was probably linked with higher P utilization and decreased bone resorption through improved intestinal integrity and gut microbiota and through decreased systemic inflammation.

The effects of pharmacological levels of zinc, diet acidification, and dietary crude protein on growth performance in nursery pigs.

This experiment was conducted to evaluate potential replacements for pharmacological levels of Zn (provided by Zn oxide), such as diet acidification (sodium diformate) and low dietary crude protein (CP: 21 vs 18%) on nursery pig performance and fecal dry matter (DM). A total of 360 weaned pigs (Line 200 × 400, DNA, Columbus, NE; initially 5.90 ± 0.014 kg) were used in a 42-d growth study. Pigs were weaned at approximately 21 d of age and randomly assigned to pens (five pigs per pen). Pens were then allotted to one of eight dietary treatments with nine pens per treatment. Experimental diets were fed in two phases: phase 1 from weaning to day 7 and phase 2 from days 7 to 21, with all pigs fed the same common diet from days 21 to 42. The eight treatment diets were arranged as a 2 × 2 × 2 factorial with main effects of Zn (110 mg/kg from days 0 to 21 or 3,000 mg/kg from days 0 to 7, and 2,000 mg/kg from days 7 to 21), diet acidification, (without or with 1.2% sodium diformate), and dietary CP (21% or 18%, 1.40% and 1.35% in phases 1 and 2 vs. 1.20% standardized ileal digestible Lys, respectively). Fecal samples were collected weekly from the same three pigs per pen to determine DM content. No 2- or 3-way interactions (P > 0.05) were observed throughout the 42-d study for growth performance; however, there was a Zn × acidifier × CP interaction (P < 0.05) for fecal DM on day 7 and for the overall average of the six collection periods. Reducing CP without acidification or pharmacological levels of Zn increased fecal DM, but CP had little effect when ZnO was present in the diet. From days 0 to 21, significant (P < 0.05) main effects were observed where average daily gain (ADG) and gain:feed (G:F) increased for pigs fed pharmacological levels of Zn, sodium diformate, or 21% CP (P < 0.065). In the subsequent period (days 21 to 42) after the experimental diets were fed, there was no evidence of difference in growth performance among treatments. Overall (days 0 to 42), main effect tendencies were observed (P < 0.066) for pigs fed added Zn or sodium diformate from days 0 to 21, whereas pigs fed 21% CP had greater G:F than those fed 18% CP. Pig weight on day 42 was increased by adding Zn (P < 0.05) or acidifier (P < 0.06) but not CP. In summary, none of the feed additives had a major influence on fecal DM, but dietary addition of pharmacological levels of Zn or sodium diformate independently improved nursery pig performance.

94 The Effects of Dietary Crude Protein, Acidifier, and Pharmacological Levels of Zinc on Growth Performance of Nursery Pigs

Abstract Weanling pigs (n = 360, DNA 200 × 400, initially 5.90 kg) were used to evaluate pharmacological levels of Zn (ZnO), diet acidification (sodium diformate; Addcon, Bitterfeld-Wolfen, Germany), and crude protein (18 or 21% CP) on pig performance. At weaning, pigs were assigned to treatments with 5 pigs/pen and 9 pens/treatment. Treatments were arranged in a 2×2×2 factorial with main effects of Zn (110 mg/kg from d 0 to 21 or 3,000 mg/kg from d 0 to 7, and 2,000 mg/kg from d 7 to 21), diet acidification (without or with 1.2% sodium diformate), and dietary CP (21 or 18%). The 21% CP diets were formulated to 1.40 and 1.35% SID Lys in phase 1 and 2, respectively, and 18% CP diets were formulated to 1.20% SID Lys. Experimental diets were fed from d 0 to 21 with a common diet from d 21 to 42. Fecal samples were collected weekly to determine fecal dry matter (DM). Data were analyzed using R Studio as a RCBD. From d 0 to 21, ADG and G:F increased (P &amp;lt; 0.05) for pigs fed pharmacological Zn, and sodium diformate. Overall, ADG tended (P ≤ 0.069) to increase for pigs fed added Zn or sodium diformate. Pigs fed 21% CP had increased (P &amp;lt; 0.05) ADG and G:F from d 0 to 21 and overall G:F compared with those fed 18% CP. Feeding 18% CP diets increased fecal dry matter on d 7 when pharmacological Zn and sodium diformate were not in the diet (Zn×acidifier×CP interaction, P &amp;lt; 0.05). From d 21 to 42, there was no evidence of difference in growth performance. In conclusion, reducing CP without acidification increased fecal DM when pharmacological Zn were not in the diet, but had little effect when it was in the diet. Adding sodium diformate and pharmacological Zn independently improved nursery pig growth performance.

182 The effects of pure benzoic acid, an acid blend product, or their combination in nursery pig diets on post-weaning growth performance

Abstract A total of 1,325 pigs (Camborough × line 800, PIC Canada) were weaned (20 d of age, 5.5 kg BW) and used to compare the effects of 5 diet acidification strategies on growth performance from d 0 to 41 post-weaning. Feed acidification strategies were fed over 3 dietary phases; d 0 to 13 (P1), d 13 to 20 (P2), and d 20 to 41 (P3). The 5 strategies consisted of 1) NC, commercial diet without any acidifier; 2) P+, NC with recommended 0.1% of an acidifier and flavoring blend (fumaric, sorbic, malic, citric acids with thymol, vanillin, eugenol) in P1, 0.05% in P2, and nothing added in P3; 3) VH, NC with 0.5% pure benzoic acid (VevoVitall®; DSM Nutritional Products) in P1, P2, and P3; 4) VL, NC with 0.25% pure benzoic acid in P1, P2, and P3; and 5) P+V, P+ with 0.5% pure benzoic acid in P1, 0.25% pure benzoic acid in P2, and nothing added in P3. Experimental additives were substituted for wheat in the basal diets. There were 10 pens of 26-27 pigs allotted to each acidification strategy in a RCBD based on initial BW. During P1, ADG, F/G, and d 13 BW were improved (P&amp;lt; 0.05) for pigs fed VH or P+V. In P2, ADG and d 20 BW were improved (P&amp;lt; 0.05) for pigs fed VH or P+V, and there was a tendency (P=0.06) for pigs fed acids (P+, VH, VL, or P+V) to have greater ADFI; however, there were no differences in F/G. There were no differences in growth performance during P3 or overall (d 0 to 41). Nevertheless, performance differences during P1 and P2 resulted in pigs fed an acidification strategy using pure benzoic acid (VH, VL, or P+V) having numerically greater BW (+0.5 kg) and income-over-feed-cost (+CA $0.44/pig) on d 41 when compared to pigs fed NC or P+.

Evaluating the Effects of Pharmacological Levels of Zinc Oxide, Diet Acidification and Dietary Crude Protein on Growth Performance of Nursery Pigs

A total of 360 weaned pigs (DNA 200 × 400; initially 12.9 lb BW) were used in a 42-d growth study to evaluate the effects of pharmacological levels of zinc oxide (ZnO), diet acidification, and dietary crude protein (CP) on pig performance. Pigs were weaned at approximately 21-d of age and were randomly assigned to pens (5 pigs per pen) and allotted to 1 of 8 dietary treatments with 9 pens per treatment. Experimental diets were fed from d 0 to 21 with a common diet fed from d 21 to 42. The eight treatment diets were arranged as a 2 × 2 × 2 factorial with main effects of Zn from ZnO (110 ppm from d 0 to 21 or 3,000 ppm from d 0 to 7, and 2,000 ppm from d 7 to 21), diet acidification, (without or with 1.2% sodium diformate), and dietary CP (21 or 18%, [1.40 vs. 1.20% standardized ileal digestible Lys, respectively]). Fecal samples were collected weekly to determine dry matter content. No 2- or 3-way interactions (P > 0.05) were observed throughout the 42-d growth study for growth performance; however, there was a ZnO × acidifier × CP interaction (P < 0.05) for fecal dry matter on d 7 and overall, where reducing CP without acidification increased fecal DM when ZnO was not in the diet, but had little effect when ZnO was present in the diet. From d 0 to 21, pigs fed added ZnO had improved (P < 0.05) average daily gain (ADG), average daily feed intake (ADFI), feed efficiency (F/G), and increased d 21 body weight (BW) compared to those fed 110 ppm Zn. Added sodium diformate improved (P < 0.05), ADG, F/G, and BW. Pigs fed 21% CP had improved (P < 0.05) ADG and F/G and tended (P < 0.10) to have increased d 21 BW. In the subsequent period (d 21 to 42) after the experimental diets were fed, there was no evidence of difference in growth perfor­mance among treatments. Overall (d 0 to 42), adding ZnO or sodium diformate from d 0 to 21 tended to increase ADG (P ≤ 0.10) with no evidence of difference in ADFI and F/G. Increasing dietary CP from 18 to 21% from d 0 to 21 improved (P < 0.05) overall F/G. In summary, dietary addition of ZnO or sodium diformate independently improved nursery pig performance.

Effects of organic acids on the gut ecosystem and on the performance of broiler chickens

Organic acids are studied as candidate alternatives to antibiotic growth promoters. Their action is related to the pH reduction of the intestinal digesta, affecting the gut ecosystem in numerous ways. Intestinal microbiota can be altered as a result of the remarkable antibacterial activity of organic acids and the growth enhancement of non-pathogenic beneficial microorganisms, due to exclusive competition. Antibacterial activity has been widely reported for many poultry pathogens, such as Salmonella spp., Escherichia coli, Clostridium perfringens, Campylobacter spp., both in vitro and in vivo. However, it seems to depend on many factors concerning the weak acid used and the gut ecosystem. Apart from the microbiota, diet supplementation of organic acids has trophic effects on the intestinal mucosa, modifying the morphologic characteristics of intestinal villi and crypts and maintaining epithelial integrity. Furthermore, as found recently, organic acids have anti-inflammatory and immunostimulating properties. Diet acidification increases gastric proteolysis and the utilization of proteins and amino acids, affects pancreatic secretions and mineral absorption. There are also reports for an effect on appetite and palatability of the feed. All these properties attributed to organic acids have either a direct or indirect effect on the performance and health, even though the results presented for poultry lack consistency. Nonetheless, the benefits of organic acids can have practical application in the control of clinical and subclinical conditions, but more research is needed to study these perspectives.

The effect of Diet Acidification with Hydrochloric and Butyric Acids on Performance, Apparent Protein Digestibility, Length and Microbial Count of Small Intestine in Broiler Chickens

The effect of Diet Acidification with Hydrochloric and Butyric Acids on Performance, Apparent Protein Digestibility, Length and Microbial Count of Small Intestine in Broiler Chickens

Response of Nile tilapia (Oreochromis niloticus) to diet acidification: Effect on growth performance and feed utilization

ABSTRACTA 12-week feeding trial was undertaken to assess growth, nutrient utilization, some hematological parameters, and proximate composition of Nile tilapia (Oreochromis niloticus) fed diets supplemented with graded levels (0.5%, 1.0%, and 1.5%) of two blends of organic acids or organic salts. Seven isonitrogenous (300 g CP kg−1) and isocaloric (19.0 MJ gross energy kg−1) diets were formulated. The control diet (D1) contained neither added blend of organic acids nor organic salts. Three diets (D2, D3, and D4) were supplemented with 0.5%, 1.0%, and 1.5% of malic acid + oxalic acid blend (OAB), respectively. The other three diets (D5, D6, and D7) were supplemented with 0.5%, 1.5%, and 1.5% of calcium lactate + sodium acetate blend (OSB), respectively. Fingerlings (7.05 ± 0.02 g) were randomly distributed into 21 glass aquaria (160 liter), with each aquarium holding 15 fish. At the end of the feeding trial, O. niloticus offered the control diet showed lower growth and feed utilization than all those fed the organic acids or organic salts blends supplemented diets. Fish fed the diet D3 showed the highest body weight (BW), body length (BL), weight gain (WG), specific growth rate (SGR), feed intake (FI), and the best feed conversion ratio (FCR) and protein efficiency ratio (PER). Fish fed diet supplemented by 1.5% OAB (D4) showed the highest serum protein content, while control group (D1) showed the lower level of total lipids compared with the other treatments. Fish group fed the diet supplemented with 0.5% of OSB (D5) showed the highest protein and ash contents and the lowest lipid content of the whole fish body, while the control group showed the lowest protein and the highest fat content. The present observations suggest that the growth, feed utilization, and health status of juvenile O. niloticus can be enhanced with a supplementation of 1% of OAB or OSB in the diet.

The effect of long-term acidifying feeding on digesta organic acids, mineral balance, and bone mineralization in growing pigs

Acidification of slurry through dietary manipulation of urinary pH is a means of mitigating nitrogen emission from pig production, but long-term effects of diet acidification on bone mineralization and mineral balance is less investigated. The objective was therefore to study the long-term effects of feeding benzoic acid (BA) and calcium chloride (CaCl2) on the mineral balance and microbial activity in the gastrointestinal tract of pigs. Four diets containing the combinations of 0 or 10g/kg BA and 0 or 20g/kg CaCl2 were fed to 24 pigs in a factorial design. For the diets without CaCl2, calcium carbonate (CaCO3) was added to provide equimolar levels of Ca. The pigs were fed the diets from 36kg until slaughter at 113kg BW, and they were housed in balance cages for 12d from 60 to 66kg BW. Supplementation of BA and/or CaCl2 had only minor effect on accumulation of digesta organic acids (acetate, propionate, butyrate and lactate) throughout the gastrointestinal tract. A reduction (P<0.01) in digesta concentration was, however, observed for acetate and propionate in colon digesta for the CaCl2 supplemented diet. Moreover, CaCl2 supplementation reduced (P<0.01) the gastric concentration of lactic acid. In the urine, pH was reduced by both BA (P=0.04) and CaCl2 (P<0.01). The diet with combined BA and CaCl2 resulted in the lowest retentions of both P (P=0.03) and Ca (P<0.01). Metacarpal III bones were lighter (P=0.04) and shorter (P=0.02) when replacing CaCO3 with CaCl2, but BA supplementation had no effect. Both replacing CaCO3 with CaCl2 and BA supplementation reduced the concentration in bone of P (P<0.05), whereas the Ca concentration was not affected. Total mineral density in bones measured by CT-scanning was reduced (P<0.01) in the medial and distal sections by BA and reduced (P<0.01) in the proximal, medial, and distal sections by CaCl2. In conclusion, the dietary supplementation of BA and the replacement of CaCO3 with CaCl2 affected the nutrient balances of P and Ca. Mineral concentration and total mineral density of metacarpal III bones was reduced both by BA supplementation and by replacing CaCO3 with CaCl2. The combined effect of BA and by replacing CaCO3 with CaCl2 may reduce bone strength during long-term feeding.

Effects of diet acidification and xylanase supplementation on performance, nutrient digestibility, duodenal histology and gut microflora of broilers fed wheat based diet

1. The objective of this experiment was to study the influences of xylanase and citric acid on the performance, nutrient digestibility, digesta viscosity, duodenal histology, and gut microflora of broilers fed on a wheat based diet. 2. The experiment was carried out as a 2 × 3 factorial arrangement with two concentrations of xylanase (0 and 200 mg/kg) and three concentrations of citric acid (0, 20 and 40 g/kg). A total of 408 one-day-old chickens with similar body weight were distributed into 24 pens with 17 birds/pen. Each dietary treatment was given to 4 replicate pens from 0 to 24 d of age. To determine the apparent nutrient digestibility, chromic oxide (3 g/kg) was added to the diets as an indigestible marker. 3. Xylanase significantly increased body weight gain at 24 d of age by 1·4% and improved gain-to-feed (G:F) by 3·6%. The inclusion of 40 g/kg citric acid decreased feed intake and body weight gain by 15·4% and 11·8%, respectively. The inclusion of 20 g/kg of citric acid decreased feed intake, but it did not affect body weight gain of broilers at 24 d of age. The inclusion of 20 and 40 g/kg citric acid improved G:F by 3·8 and 4·3% respectively. Xylanase significantly decreased the viscosity of digesta and improved retention of DM, CP, and energy. 4. Xylanase and citric acid did not have any effect on the histo-morphology of the duodenum and intestinal microbial population. 5. In conclusion, citric acid at 20 g/kg decreased feed intake, did not have a negative effect on body weight gain, and improved G:F. Xylanase decreased digesta viscosity, increased nutrient retention and consequently improved performance of broilers fed on a wheat based diet.

English

A concern about enhancing the natural defense mechanisms of animals and reducing the massive use of antibiotics led to the banning of studies in this field. So, this research was done to investigate the effect of butyric acid glycerides and salinomycin sodium on the performance of the broiler chickens (strain Ross 308). A total of 800 chickens were reared for 42 days. A 3 factor statistical design was conducted with 4 replicates, and each factor contained 2 levels (25 broilers in each pen). The factors were butyric acid glycerides (0 and 0.3% of diet), salinomycin sodium - an anticoccidial drug (0 and 0.5% of diet) - and litter moisture (normal litter with average moisture of 35% and wet litter with average moisture of 75%). Data were collected and analyzed by SAS with GLM procedure. The results showed that butyric acid glycerides had no significant effect on feed intake. Weight gain and feed conversion ratio were not significantly affected by the mentioned factors. The effect of the treatments on the number of Eimeria oocytes excreta in the second and fourth week of breeding and feed intake were significant (p&lt;0.05). Diet acidification with butyric acid glycerides caused an increase in ash, calcium and phosphorus of the chicken tibia, but this increase was not significant (p&gt;0.05). Considering the result of this experiment, the use of butyric acid glycerides and salinomycin sodium in the aforementioned levels had no positive effect on the performance of broiler chickens (p&gt;0.05). &nbsp; Key words:&nbsp;Butyric acid glycerides, salinomycin sodium, ross, performance and broilers.

Urine acidification has no effect on peroxisome proliferator-activated receptor (PPAR) signaling or epidermal growth factor (EGF) expression in rat urinary bladder urothelium

We previously reported prevention of urolithiasis and associated rat urinary bladder tumors by urine acidification (via diet acidification) in male rats treated with the dual peroxisome proliferator-activated receptor (PPAR)α/γ agonist muraglitazar. Because urine acidification could potentially alter PPAR signaling and/or cellular proliferation in urothelium, we evaluated urothelial cell PPARα, PPARδ, PPARγ, and epidermal growth factor receptor (EGFR) expression, PPAR signaling, and urothelial cell proliferation in rats fed either a normal or an acidified diet for 5, 18, or 33 days. A subset of rats in the 18-day study also received 63 mg/kg of the PPARγ agonist pioglitazone daily for the final 3 days to directly assess the effects of diet acidification on responsiveness to PPARγ agonism. Urothelial cell PPARα and γ expression and signaling were evaluated in the 18- and 33-day studies by immunohistochemical assessment of PPAR protein (33-day study only) and quantitative real-time polymerase chain reaction (qRT-PCR) measurement of PPAR-regulated gene expression. In the 5-day study, EGFR expression and phosphorylation status were evaluated by immunohistochemical staining and egfr and akt2 mRNA levels were assessed by qRT-PCR. Diet acidification did not alter PPARα, δ, or γ mRNA or protein expression, PPARα- or γ-regulated gene expression, total or phosphorylated EGFR protein, egfr or akt2 gene expression, or proliferation in urothelium. Moreover, diet acidification had no effect on pioglitazone-induced changes in urothelial PPARγ-regulated gene expression. These results support the contention that urine acidification does not prevent PPARγ agonist-induced bladder tumors by altering PPARα, γ, or EGFR expression or PPAR signaling in rat bladder urothelium.

Effects of water and diet acidification with and without antibiotics on weanling pig growth and microbial shedding1,2

Two 5-wk experiments were conducted to determine the effects of water and diet acidification with and without antibiotics on weanling pig growth performance and microbial shedding. In Exp. 1, 204 pigs (19.2 d of age) were used in a 3 x 2 factorial, with 3 dietary treatments fed with or without water acidification (2.58 mL/L of a propionic acid blend; KEM SAN, Kemin Americas, Des Moines, IA). Dietary treatments were: 1) control, 2) control + 55 ppm of carbadox (CB), and 3) dietary acid [DA; control + 0.4% organic acid-based blend (fumaric, lactate, citric, propionic, and benzoic acids; Kemin Americas)] on d 0 to 7 followed by 0.2% inorganic acid-based blend (phosphoric, fumaric, lactic, and citric acids; Kemin Americas) on d 7 to 34. In Exp. 2, 210 pigs (average 18.3 d of age) were fed 1 of 3 dietary treatments: 1) control, 2) control + 55 ppm of CB, and 3) control + 38.6 ppm of tiamulin + 441 ppm of chlortetracycline on d 0 to 7 followed by 110 ppm of chlortetracycline on d 7 to 35 (TC) with or without dietary acidification (same as Exp. 1) in a 3 x 2 factorial arrangement of treatments. For both experiments, the pigs were allotted based on genetics, sex, and initial BW [5.5 kg (Exp. 1) or 5.6 kg (Exp. 2)]. Pigs were housed at 6 or 7 (Exp. 1) and 7 (Exp. 2) pigs/pen. Treatments were fed in 3 phases: d 0 to 7, 7 to 21, and 21 to 35 (34 d, Exp. 1). Fecal grab samples were collected from 3 pigs/pen on d 6, 20, and 33 for measurement of pH and Escherichia coli. During phase 3 and overall in Exp. 1, pigs fed CB had greater (P < 0.001) ADG (overall ADG, 389 vs. 348, and 348 g/d, respectively), ADFI (P < 0.007, 608 vs. 559, and 554 g/d, respectively), and d 34 BW (P < 0.001, 18.8 vs. 17.3, and 17.3 kg, respectively) than pigs fed NC and DA. Phase 3 ADG was improved (P < 0.01) by water acidification across all diets. In Exp. 2, pigs fed CB and TC had greater ADG (P < 0.004; 315 and 303 vs. 270 g/d, respectively), ADFI (P < 0.01), and d 35 BW (P < 0.002; 16.7 and 16.2 vs. 15.1 kg, respectively) than pigs fed NC. There was a tendency (P < 0.08) for an improvement in ADG when DA was added to the NC or TC, but decreased ADG when DA was added to CB.

Selected culturable enteric bacterial populations are modified by diet acidification and the growth promotant Tylosin

To determine the effect of diet acidification and an in-feed antibiotic growth promotant (Tylosin, Ty) on selected culturable bacterial populations in the gastrointestinal tract (GIT) of mice. Female C57Bl mice were given a standard diet supplemented with Acid Pak (AP) or Ty in the drinking water. After 21 days, lumen and adherent populations of Enterobacteriaceae, enterococci/streptococci, and lactic acid bacteria (LAB) from the ileum, caecum, colon and faeces were enumerated. General intestinal health was assessed by the frequency of haemolytic bacteria in the different intestinal compartments. Contrary to expectations, AP and Ty significantly increased haemolytic bacteria in the lumen of the caecum and colon (P<0.05). The small but significant growth-enhancing effect of Ty (P<0.05) was associated with decreases in enterococci/streptococci and surprisingly, LAB, as well as increases in coliforms. AP, which failed to improve growth rates, reduced coliforms, had limited effects on enterococci/streptococci, and specifically failed to promote the growth of LAB populations in all intestinal compartments. Ty supplementation was also associated with a significant increase in macrolide-resistant enterococci throughout the GIT. Dietary acidification is less effective than Ty in modulating the population dynamics of selected culturable populations of enteric bacteria. The mouse can provide a useful experimental model to examine the effects of new dietary supplements, formulations or regimes on changes in microbial population dynamics, including monitoring for antibiotic resistance.

Acidification of weaner pig diets: A review

AbstractThe potential of diet acidification to overcome the digestive insufficiency and postweaning lag in early weaned pigs is examined in the review. A survey of published data on various types of acidifiers reveal considerable variation in response to acidification of weaner diets. Several reasons may be proposed to explain the inconsistencies in response, these include differences in diet type, age of pigs, type and level of acidifier, and existing performance levels. Reducing the gastric pH does not appear to be the primary effect of acidifiers. Acidification, however, consistently suppressed pathogenic coliforms in the gastrointestinal tract. Future developments in the use of acidifiers would be intrinsically linked to the understanding of their mode(s) of action in the animal.

Citric acid and fumaric acid as food additives for early-weaned piglets

ABSTRACTThe effects of diet acidification on the growth performance of piglets were assessed in two experiments. In the first, 167 piglets were weaned at 10 days of age and penned in litter-mate groups (seven groups per treatment) which were allocated to one of three diets, with either citric acid (30 g/kg; C), fumaric acid (15 g/kg; F) or no additional organic acid (N); pigs were fed ad libitum for 25 days. The rate of live-weight gain was significantly higher for treatment C than for treatments F or N (216 (s.e. 10), 170 (s.e. 7) and 189 (s.e. 6) g/day respectively; P &lt; 0·05). The voluntary food intake on treatment C also tended to be higher than on the other two diets (220 (s.e. 24), 182 (s.e. 18) and 189 (s.e. 7) g/day for treatments C, F and N respectively).In experiment 2, 30 crossbred piglets were penned in single-sex groups of three and weaned at 10 days of age. The same diets were used as in experiment 1 but all three diets were available ad libitum to each group of piglets for 25 days. When dietary choice was allowed, piglets consumed significantly greater quantities of the control diet than of the acidified diets (1381, 1422, 2972 (s.e. 132) g/day for diets C, F and N respectively; P &lt; 0·01). When the relative intake of each diet was correlated with live-weight gain, only diet C showed a significant positive correlation (r = +0·74; P &lt; 0·05). Correlations of F and N intakes with live-weight gain were negative. It is concluded that citric acid (30 g/kg) in the diet of early-weaned piglets promotes live-weight gain, although acidification of the diet may decrease palatability.