Dietary self-selection for organic acids by the piglet

Effects of dietary organic acid and pure botanical supplementation on growth performance and circulating measures of metabolic health in Holstein calves challenged by heat stress

To evaluate the effects of heat stress environmental conditioning and dietary supplementation with organic acid and pure botanicals (OA/PB) on growth in dairy calves, we enrolled 62 bull (noncastrated) and heifer calves in a study with a completely randomized design. Calves were assigned to 1 of 5 groups (n = 11 to 14/group): (1) thermoneutral conditions (TN-Con), (2) HS conditions (HS-Con), (3) thermoneutral conditions and pair-fed to match nutrient intake with HS-Con (TN-PF), (4) HS with low-dose OA/PB [75 mg/kg of body weight (BW); 25% citric acid, 16.7% sorbic acid, 1.7% thymol, 1.0% vanillin, and 55.6% triglyceride; HS-Low], or (5) HS with high-dose OA/PB (150 mg/kg of BW; HS-High). Supplements were delivered as a twice-daily bolus via the esophagus from wk 1 through 13 of life; all calves, including those on the control treatments, received an equivalent amount of triglyceride used for microencapsulation. Calves were raised in TN conditions from birth until weaning. After weaning, calves (62 ± 2 d; 91 ± 10.9 kg of BW) were transported to a new facility and remained in TN conditions [temperature-humidity index (THI): 60 to 69] for a 7-d covariate period. Thereafter, calves remained in TN or were moved to HS conditions (THI: diurnal change 75 to 83 during night and day, respectively) for 19 d. Clinical assessments were performed thrice daily, BW was recorded weekly, and blood was sampled on d 1, 2, 3, 8, 15, and 19. Upon experiment completion, calves from HS-Con and TN-Con were euthanized, and hot carcass and visceral organ weights were recorded. The mixed model included calf as a random effect; treatment, day, hour (when appropriate) as fixed effects, and the interactions of treatment × day and treatment × hour (when appropriate). Rectal and skin temperatures and respiration rates were greater in HS-Con than in TN-Con. During heat stress exposure, dry matter intake (DMI), average daily gain (ADG), and gain to feed (G:F) were lower in HS-Con relative to TN-Con. Comparing HS-Con and TN-PF, ADG and G:F were similar. Plasma fatty acid concentrations were elevated in TN-PF compared with HS-Con and TN-Con. Despite tendencies for increased aspartate aminotransferase, HS conditions did not overtly influence liver and inflammation markers. Liver weights were lower in HS-Con relative to TN-Con. During the first week of heat exposure, DMI was greater for HS-Low relative to HS-Con. Supplementation of OA/PB at low and high levels had a similar G:F to HS-Con. We conclude that reductions in DMI accounted for production losses during HS conditioning and that dietary OA/PB supplementation was not able to improve growth performance in heat-stressed calves.

Impact of bioactive substances on the gastrointestinal tract and performance of weaned piglets: a review

The EU ban on in-feed antibiotics has stimulated research on weaning diets as a way of reducing post-weaning gut disorders and growth check in pigs. Many bioactive components have been investigated but only few have shown to be effective. Amongst these, organic acids (OA) have been shown to exert a bactericidal action mediated by non-dissociated OA, by lowering gastric pH, increasing gut and pancreas enzyme secretion and improving gut wall morphology. It has been postulated that they may also enhance non-specific immune responses and improve disease resistance. In contrast, relatively little attention has been paid to the impact of OA on the stomach but recent data show they can differently affect gastric histology, acid secretion and gastric emptying. Butyrate and precursors of butyric acid have received special attention and although promising results have been obtained, their effects are dependent upon the dose, treatment duration, initial age of piglets, gastrointestinal site and other factors. The amino acids (AA) like glutamine, tryptophan and arginine are supportive in improving digestion, absorption and retention of nutrients by affecting tissue anabolism, stress and (or) immunity. Glutamine, cysteine and threonine are important for maintaining mucin and permeability of intestinal barrier function. Spray-dried plasma (SDP) positively affects gut morphology, inflammation and reduces acquired specific immune responses via specific and a-specific influences of immunoglobulins and other bioactive components. Effects are more pronounced in early-weaned piglets and under poorer health conditions. Little interaction between plasma protein and antibiotics has been found, suggesting distinct modes of action and additive effects. Bovine colostrum may act more or less similarly to SDP. The composition of essential oils is highly variable, depending on environmental and climatic conditions and distillation methods. These oils differ widely in their antimicrobial activity in vitro and some components of weaning diets may decrease their activity. Results in young pigs are highly variable depending upon the product and doses used. These studies suggest that relatively high concentrations of essential oils are needed for beneficial effects to be observed and it has been assumed that these plant extracts mimic most of the effects of antibiotics active on gut physiology, microbiology and immunology. Often, bioactive substances protective to the gut also stimulate feed intake and growth performance. New insights on the effects of selected OA and AA, protein sources (especially SDP, bovine colostrum) and plant extracts with anti-bacterial activities on the gut are reported in this review.

Sorbic acid improves growth performance and regulates insulin-like growth factor system gene expression in swine

Sorbic acid (SA) is a PUFA with a conjugated double bond. The conjugated fatty acids, including CLA, are multifunctional bioactive fatty acids with the ability to improve growth performance. The effect of SA on pig growth performance was examined to determine its mechanism of action. The ADG, ADFI, and serum IGF-I concentration were examined, as were IGF-I secretion and IGF system gene expression in hepatocytes. Two hundred forty 21-d-old Duroc × Landrace × Yorkshire weaned piglets (6.86 ± 0.02 kg) were randomly divided into 4 groups, each consisting of 3 pens of 20 piglets (10 female and 10 male). The 4 groups of piglets were kept in a temperature-controlled room (26 to 28 °C), and feed and water were provided to the pigs ad libitum. Weanling piglets were fed diets that included 0, 0.5, 2, or 4 g of SA/kg for 42 d. The diet supplemented with 0.5 g/kg of SA improved (P < 0.05) ADG, BW, and G:F, whereas supplementation with all 3 SA doses increased (P < 0.05) ADG and G:F at 21 to 42 d of age. The greatest concentration of plasma triglycerides was observed (P < 0.05) in the 4 g/kg of SA group. The SA increased (0.5 g of SA/kg, P > 0.05; 1 g of SA/kg, P < 0.05; and 2 g of SA/kg, P < 0.05, respectively) plasma total serum protein and globulin concentrations in a dose-dependent manner. It was noted that the smallest SA treatment dose (0.5 g/kg) dramatically increased (P < 0.05) serum IGF-I concentration but decreased (P < 0.05) the concentrations of blood urea N and cortisol. The SA increased (P < 0.05) IGF-I, IGF-II, IGF-I receptor (IGF-IR), and PPARα gene mRNA expression and IGF-I secretion, but not (P > 0.05) IGFBP or PPARγ mRNA expression, in pig primary hepatocytes. These results indicate that SA improves growth performance by regulating IGF system gene expression and hormone secretion.

Feed preferences and performance of nursery pigs fed diets containing various inclusion amounts and qualities of distillers coproducts and flavor

We evaluated the preferences of nursery pigs for diets containing increasing distillers dried grains with solubles (DDGS), varying in color, or high-protein distillers dried grains (HP-DDG) and the effects of flavor supplementation on pig preference and growth performance. In Exp. 1 through 5, diet preference was determined in weanling pigs adjusted to a commercial diet for at least 10 d, and then housed individually for a 2-d double-choice preference test. In Exp. 1, a total of 60 pigs (11.6 ± 0.3 kg of BW) were given a choice between a reference diet (0% DDGS) and test diets containing 0, 10, 20, or 30% DDGS. In Exp. 2, a total of 80 pigs (10.8 ± 0.1 kg of BW) were given a choice between a reference diet (0% HP-DDG) and diets containing 0, 10, 20, or 30% HP-DDG. In Exp. 3, a total of 80 pigs (10.3 ± 0.2 kg of BW) were given a choice between a reference diet (0% DDGS) and a diet containing 0%, 30% light, or 30% dark DDGS. In Exp. 4, a total of 80 pigs (11.2 ± 0.2 kg of BW) were given a choice between a reference diet without DDGS and a diet containing either 0% DDGS, 10 or 20% light DDGS, or 10 or 20% dark DDGS. In Exp. 5, a total of 108 pigs (9.0 ± 0.2 kg of BW) were given a choice between a reference diet (0% DDGS and no flavor) and a diet without or with flavor and containing 0, 10, or 20% DDGS. In Exp. 1 and 2, DDGS and HP-DDG, respectively, linearly decreased (P < 0.01) pig preference. In Exp. 3, dark DDGS were preferred (P < 0.05) compared with light DDGS. In Exp. 4, preferences were linearly reduced (P < 0.01) with DDGS inclusion, and dark DDGS tended (P = 0.06) to be preferred compared with light DDGS. In Exp. 5, DDGS reduced preference (P < 0.01) and flavor reduced preference (P < 0.01) regardless of DDGS level. In Exp. 6, a total of 192 pigs (6.7 ± 0.1 kg of BW) were fed starter 1 diets without or with flavor for 1 wk. Subsequently, pigs were fed starter 2 and 3 diets (2 wk each) containing 0, 10, or 20% DDGS while continuing to receive their respective flavor treatment. Flavor addition during the starter 1 phase increased ADFI (P = 0.02), and DDGS inclusion tended to decrease ADG (P = 0.06) and decreased ADFI (P = 0.03) during the starter 2 phase. Volatile components in DDGS and HP-DDG varied greatly depending on the source. Nursery pigs preferred a diet without DDGS or HP-DDG, and this appeared to be unrelated to color differences between sources. Knowledge of volatile compounds that enhance or suppress the palatability of feed may lead to further development of feed additives for masking relatively unpalatable, albeit cost-effective, ingredients.

Ácido fumárico e sua combinação com os ácidos butírico ou fórmico em dietas de leitões recém desmamados

Avaliaram-se o desempenho e as características morfológicas e morfométricas do intestino delgado de 210 leitões, desmamados aos 15 dias de idade, com peso médio inicial 4,04±0,66kg, em dois períodos experimentais (15-30 e 15-36 dias de idade). O delineamento experimental foi em blocos ao acaso, com sete tratamentos (T1: ração-controle sem adição de acidificante; T2: ração-controle + 0,5% de ácido fumárico; T3: ração-controle + 1,0% de ácido fumárico; T4: ração-controle + 0,5% de ácido fumárico +0,1% de ácido butírico; T5: ração-controle + 0,5% de ácido fumárico + 0,5% de ácido fórmico; T6: ração-controle + 1,0% de ácido fumárico + 0,1% de ácido butírico e T7: ração-controle + 1,0% de ácido fumárico +0,5% de ácido fórmico), cinco repetições e seis animais por unidade experimental. O peso dos leitões aos 30 dias de idade não foi influenciado pelos tratamentos, mas houve efeito significativo de tratamento sobre ganho de peso e consumo alimentar diário no período de 15-30 dias de idade, com maior desempenho para os leitões alimentados com dietas suplementadas com ácido fumárico. Não houve efeito significativo dos tratamentos sobre o peso médio aos 36 dias, o ganho de peso, o consumo diário e a conversão alimentar dos leitões de 15 a 36 dias de idade. Houve diferença entre tratamentos para a altura do epitélio do duodeno, porém não houve diferença em relação à do jejuno e à do íleo. As eletromicrografias do duodeno dos leitões alimentados com as diferentes dietas experimentais revelaram vilosidades com características normais.

Response of pigs to dietary inclusion of formic acid and ammonium formate1,2

The objective of this study was to determine the optimal inclusion rate of dietary formic acid-ammonium formate (composition by weight was 62% formic acid and 37% ammonium formate) in nursery and grower-finisher diets or grower-finisher diets only. At weaning (d 21 +/- 2), 224 pigs (equal numbers of gilts and barrows) were blocked by BW within sex (28 pigs per BW block, 4 pigs per pen) and assigned randomly to 1 of 7 dietary treatments within each block. Dietary treatments (TRT), listed as percentage of dietary formic acid-ammonium formate in the nursery (NR) and the grower-finisher (GRF) diets, were as follows (NR and GRF): TRT 1: 0.0 and 0.0; TRT 2: 1.2 and 1.0; TRT 3: 0.0 and 1.0; TRT 4: 1.0 and 0.8; TRT 5: 0.0 and 0.8; TRT 6: 0.8 and 0.6; and TRT 7: 0.0 and 0.6. During the grower 2 (GR2) period, pigs fed treatments containing formic acid-ammonium formate in the nursery diets (TRT 2, TRT 4, and TRT 6) had greater (P < 0.05) ADG and G:F than pigs fed diets containing formic acid-ammonium formate in the grower period only (TRT 3, TRT 5, and TRT 7). Average daily feed intake tended to decrease (NR1, P = 0.07) or decreased (NR2, P < 0.05) for pigs fed formic acid-ammonium formate in the nursery (TRT 2, TRT 4, and TRT 6) compared with pigs fed control diets (TRT 1, TRT 3, TRT 5, and TRT 7). The ADFI also decreased (P < 0.05) during the GR1 and GR2 periods for pigs fed diets containing formic acid-ammonium formate compared with pigs fed control (TRT 1). In the combined nursery data, there was no effect (P > 0.10) of treatment on ADG. Pigs on diets containing formic acid-ammonium formate ate less feed (P < 0.05) and had improved G:F (P < 0.05) compared with pigs on the control treatments (TRT 1, TRT 3, TRT 5, and TRT 7). Combining the grower-finisher phases, G:F was greater (P = 0.05) for pigs fed diets containing formic acid-ammonium formate than for pigs fed the control feed. The efficiency of gain (i.e., G:F) was improved by 3.5% for pigs fed all formic acid-ammonium formate treatments and ranged from 2.3 (TRT 7) to 5.9% (TRT 4) compared with pigs fed control (TRT 1). Combining all phases from nursery to finisher, the G:F ratio tended (P = 0.08) to be greater for pigs fed formic acid-ammonium formate compared with pigs fed control. The efficiency of gain was improved by 3.0% for pigs fed all formic acid-ammonium formate treatments, ranging from 1.8 (TRT 7) to 5.2% (TRT 4), compared with pigs fed the control diet (TRT 1).