Effects of altering the ratio of C16:0 and cis-9 C18:1 in rumen bypass fat on growth performance, lipid metabolism, intestinal barrier, cecal microbiota, and inflammation in fattening bulls

BACKGROUND

C16:0 and cis-9 C18:1 may have different effects on animal growth and health due to unique metabolism in vivo. This study was investigated to explore the different effects of altering the ratio of C16:0 and cis-9 C18:1 in fat supplements on growth performance, lipid metabolism, intestinal barrier, cecal microbiota, and inflammation in fattening bulls. Thirty finishing Angus bulls (626 ± 69 kg, 21 ± 0.5 months) were divided into 3 treatments according to the randomized block design: (1) control diet without additional fat (CON), (2) CON + 2.5% palmitic acid calcium salt (PA, 90% C16:0), and (3) CON + 2.5% mixed fatty acid calcium salt (MA, 60% C16:0 + 30% cis-9 C18:1). The experiment lasted for 104 d, after which all the bulls were slaughtered and sampled for analysis.

RESULTS

MA tended to reduce 0-52 d dry matter intake compared to PA (DMI, P = 0.052). Compared with CON and MA, PA significantly increased 0-52 d average daily gain (ADG, P = 0.027). PA tended to improve the 0-52 d feed conversion rate compared with CON (FCR, P = 0.088). Both PA and MA had no significant effect on 52-104 days of DMI, ADG and FCR (P > 0.05). PA tended to improve plasma triglycerides compared with MA (P = 0.077), significantly increased plasma cholesterol (P = 0.002) and tended to improve subcutaneous adipose weight (P = 0.066) when compared with CON and MA. Both PA and MA increased visceral adipose weight compared with CON (P = 0.021). Only PA increased the colonization of Rikenellaceae, Ruminococcus and Proteobacteria in the cecum, and MA increased Akkermansia abundance (P < 0.05). Compared with CON, both PA and MA down-regulated the mRNA expression of Claudin-1 in the jejunum (P < 0.001), increased plasma diamine oxidase (DAO, P < 0.001) and lipopolysaccharide (LPS, P = 0.045). Compared with CON and MA, PA down-regulated the ZO-1 in the jejunum (P < 0.001) and increased plasma LPS-binding protein (LBP, P < 0.001). Compared with CON, only PA down-regulated the Occludin in the jejunum (P = 0.013). Compared with CON, PA and MA significantly up-regulated the expression of TLR-4 and NF-κB in the visceral adipose (P < 0.001) and increased plasma IL-6 (P < 0.001). Compared with CON, only PA up-regulated the TNF-α in the visceral adipose (P = 0.01). Compared with CON and MA, PA up-regulated IL-6 in the visceral adipose (P < 0.001), increased plasma TNF-α (P < 0.001), and reduced the IgG content in plasma (P = 0.035). Compared with CON, PA and MA increased C16:0 in subcutaneous fat and longissimus dorsi muscle (P < 0.05), while more C16:0 was also deposited by extension and desaturation into C18:0 and cis-9 C18:1. However, neither PA nor MA affected the content of cis-9 C18:1 in longissimus dorsi muscle compared with CON (P > 0.05).

CONCLUSIONS

MA containing 30% cis-9 C18:1 reduced the risk of high C16:0 dietary fat induced subcutaneous fat obesity, adipose tissue and systemic low-grade inflammation by accelerating fatty acid oxidative utilization, improving colonization of Akkermansia, reducing intestinal barrier damage, and down-regulating NF-κB activation.

The form more than the fatty acid profile of fat supplements influences digestibility but not necessarily the production performance of dairy cows

The form of a lipid supplement, its degree of saturation, and its fatty acid (FA) profile greatly influence digestibility and cow productive response. The objective in this study was to examine the effect of fat supplements that differ in their form or FA profile on nutrient digestibility and cow performance. Forty-two mid-lactation cows (128 ± 53 d) were assigned to 3 treatment groups according to milk yield, days in milk, and body weight. For 13 wk, the cows were fed rations that contained (on a dry matter basis) (1) 2.4% of calcium salts of fatty acids (CSFA) consisting of 45% palmitic acid (PA) and 35% oleic acid (OA; CS45:35); (2) 2.4% of CSFA consisting of 80% PA and 10% OA (CS80:10); or (3) 2.0% of free FA consisting of 80% PA and 10% OA (FF80:10). Rumen samples were taken to measure the ammonia and volatile FA concentrations, and fecal samples were taken to measure the digestibility. Preplanned comparisons were CS45:35 versus CS80:10 to assess 2 CSFA supplements with different FA profiles, and CS80:10 versus FF80:10 to assess similar FA profiles in different forms. Compared with CS45:35, CS80:10 decreased the milk yields, increased the fat percentage, and tended to increase the energy-corrected milk (ECM) yields. The fat percentage of milk was highest in the FF80:10 cows (4.02%), intermediate in the CS80:10 cows (3.89%), and lowest in the CS45:35 cows (3.75%). Compared with CS80:10, FF80:10 increased milk yields (50.1 vs. 49.4 kg/d, respectively), tended to increase fat percentage, and increased 4% fat-corrected milk (4% FCM; 49.1 vs. 47.7 kg/d, respectively) and ECM yields (49.5 vs. 48.2 kg/d, respectively). Treatment had no effect on dry matter intake (DMI), and compared with CS80:10 cows, the calculated energy balance was lower in the FF80:10 cows. The 4% FCM/DMI and ECM/DMI ratios were higher in the FF80:10 group compared with the CS80:10 group. Compared with the CS80:10 cows, the FF80:10 cows had a lower rumen pH, higher propionate, lower acetate/propionate ratio, and higher total VFA. Compared with CS45:35 cows, the apparent total-tract digestibilities of neutral detergent fiber and acid detergent fiber were higher in CS80:10 cows; whereas, the apparent total-tract digestibilities of dry matter, organic matter, protein, neutral detergent fiber, and acid detergent fiber were higher in the CS80:10 cows compared with the FF80:10 cows. Compared with the CS80:10 group, the apparent digestibility of total FA was 13.0 percentage points lower in the FF80:10 cows (79.1 vs. 66.1%, respectively), and similarly, the digestibilities of 16-carbon and 18-carbon FA were lower in the FF80:10 cows than in the CS80:10 cows. In conclusion, the form, more than the FA profile of fat supplements, influenced digestibility. Further, the CSFA supplements were more digestible than the free fatty acids, regardless of the FA profile. However, energy partitioning toward production appeared to be higher in the FF80:10 cows, although the digestibility of nutrients was lower than in the CSFA product with a similar FA profile.

Nutrient digetibility and production responses of lactating dairy cows when saturated free fatty acid supplements are included in diets: A meta-analysis

Our objective was to perform a series of meta-analyses to evaluate the effects of diets supplemented with saturated free fatty acid (FA) supplements (SFAA) compared with nonfat supplemented control diets (CON) on nutrient digestibility and production responses of lactating dairy cows and to determine whether experimental design affects responses to SFFA. We divided SFFA into C16:0-enriched supplements (PALM, FA supplements with ≥80% C16:0) and C16:0+C18:0-enriched supplements (MIX, FA supplements with ≥80% C16:0+C18:0). The database was formed from 32 peer-reviewed publications with SFFA supplemented at ≤3% diet dry matter (DM). We completed 3 different meta-analyses to meet our objectives. We analyzed the interaction between experimental design (continuous vs. change-over) and treatments (CON vs. SFFA; Meta.1). Regardless of experimental design, we evaluated the effect of treatment (CON vs. PALM vs. MIX; Meta.2) and the effect of 1-percentage-unit increase of MIX and PALM in diet DM (Meta.3). In Meta.1, there was no interaction between treatments and experimental design for any variable. In Meta.2, compared with CON, MIX had no effect on NDF digestibility, milk protein yield and energy corrected milk (ECM), increased the yields of milk (1.20 kg/d) and milk fat (0.04 kg/d), and decreased FA digestibility (5.20 percentage units). Compared with CON, PALM increased NDF digestibility (4.50 percentage units), the yields of milk (1.60 kg/d), milk fat (0.10 kg/d), milk protein (0.04 kg/d), and ECM (2.00 kg/d), and had no effect on FA digestibility. Compared with MIX, PALM tended to increase FA digestibility (3.20 percentage units), increased NDF digestibility (3.50 percentage units), milk fat yield (0.06 kg/d), and ECM (1.20 kg/d). In Meta.3, for each 1-percentage-unit increase of supplemental FA in diet DM, MIX had no effect on NDF digestibility, decreased FA digestibility, increased the yields of milk and milk fat, had no effect on milk protein yield, ECM and milk fat content, and decreased milk protein content. For each 1-percentage-unit increase of supplemental FA in diet DM, PALM increased NDF digestibility, had no effect on FA digestibility, increased the yields of milk, milk fat, ECM and milk fat content, tended to increase milk protein yield, and had no effect on milk protein content. Our results indicate no reason for the restrictive use of change-over designs in saturated FA supplementation studies and meta-analyses. Lactating dairy cows responded better to a FA supplement enriched in C16:0 compared with one containing C16:0 and C18:0.

Effects of calcium salts of palm fatty acids on nutrient digestibility and production responses of lactating dairy cows: A meta-analysis and meta-regression

Our primary objective was to perform a meta-analysis and meta-regression to evaluate the effects of diets supplemented with calcium salts of palm fatty acids (CSPF) compared with nonfat supplemented control diets (CON) on nutrient digestibility and production responses of lactating dairy cows. Our secondary objective was to perform a meta-analysis to evaluate whether experimental design affects production responses to supplemental CSPF. The data set was formed from 33 peer-reviewed publications with CSPF supplemented at ≤3% diet dry matter. We analyzed the interaction between experimental design (continuous vs. change-over) and treatments (CON vs. CSPF) to evaluate whether experimental design affects responses to CSPF (Meta.1). Regardless of experimental design, we evaluated the effects of CSPF compared with CON on nutrient digestibility and production responses of lactating dairy cows by meta-analysis (Meta.2) and meta-regression (Meta.3) approaches. In Meta.1, there was no interaction between treatments and experimental design for any variable. In Meta.2, compared with CON, CSPF reduced dry matter intake [DMI, 0.56 ± 0.21 kg/d (±SE)] and milk protein content (0.05 ± 0.02 g/100 g), increased neutral detergent fiber (NDF) digestibility (1.60 ± 0.57 percentage units), the yields of milk (1.53 ± 0.56 kg/d), milk fat (0.04 ± 0.02 kg/d), and 3.5% fat corrected milk (FCM, 1.28 ± 0.60 kg/d), and improved feed efficiency [energy corrected milk (ECM)/DMI, 0.08 kg/kg ± 0.03]. There was no effect of treatment for milk protein yield, milk fat content, body weight, body weight change, or body condition score. Compared with CON, CSPF reduced the yield of de novo milk fatty acids (FA) and increased the yields of mixed and preformed milk FA. In Meta.3, we observed that each 1-percentage-unit increase of CSPF in diet dry matter reduced DMI, increased NDF digestibility, tended to increase FA digestibility, increased the yields of milk, milk fat, and 3.5% FCM, reduced the content of milk protein, reduced the yield of de novo milk FA, and increased the yields of mixed and preformed milk FA. In conclusion, our results indicate no reason for the restrictive use of change-over designs in CSPF supplementation studies or meta-analysis. Feeding CSPF increased NDF digestibility, tended to increase FA digestibility, and increased the yields of milk, milk fat, and 3.5% FCM. Additionally, CSPF increased milk fat yield by increasing the yields of mixed and preformed milk FA.

Milk production responses to altering the dietary ratio of palmitic and oleic acids varies with production level in dairy cows

We evaluated the effects of altering the dietary ratio of palmitic (C16:0; PA) and oleic (cis-9 C18:1; OA) acids on production responses of cows with a wide range of milk production (32 to 65 kg/d) in a crossover design experiment with a preliminary period. Thirty-two multiparous Holstein cows (144 ± 54 d in milk) were assigned randomly to a treatment sequence. Treatments were diets supplemented with fatty acid (FA) blends (1.5% of diet dry matter) that provided 80% C16:0 + 10% cis-9 C18:1 (PA) and 60% C16:0 + 30% cis-9 C18:1 (PA+OA). The corn silage and alfalfa-based diets contained 20.0% forage neutral detergent fiber (NDF), 28.5% starch, and 17.1% crude protein. Treatment periods were 21 d with the final 5 d used for data and sample collection. Treatment did not affect dry matter intake (DMI), milk yield, energy-corrected milk (ECM), body weight, or body weight change. The PA+OA diet increased total, 16-carbon, and 18-carbon FA digestibility compared with the PA diet. Compared with PA+OA, PA increased fat yield (1.97 vs. 1.91 kg/d) and protein yield (1.61 vs. 1.55 kg/d). The PA diet also increased the yield of de novo (448 vs. 428 g/d) and mixed (749 vs. 669 g/d) milk FA and decreased the yield of preformed FA (605 vs. 627 g/d) compared with PA+OA. Interactions were detected between treatment and preliminary milk yield for DMI, total FA intake, 16-carbon FA intake, ECM, 3.5% fat-corrected milk (linear interaction), and a tendency for milk yield (linear interaction); lower-producing cows (<45 kg/d) had increased DMI and ECM on the PA diet, whereas higher-producing cows (>55 kg/d) had increased DMI and ECM on the PA+OA diet. A linear interaction was detected between treatment and preliminary milk yield for mixed milk FA yield (linear interaction) and a tendency for de novo milk FA yield (linear interaction). Our results demonstrate that feeding a fat supplement containing more cis-9 C18:1 replacing C16:0 increased production responses (DMI, milk yield, and ECM) in higher-producing cows, but decreased production responses in lower-producing cows.

Effects of fatty acid profile of supplements on intake, performance, carcass traits, meat characteristics, and meat sensorial analysis of feedlot Bos indicus bulls offered a high-concentrate diet

This experiment was designed to evaluate the effects of lipid source and fatty acid (FA) profile on intake, performance, carcass characteristics, expression of enzymes, and sensorial analysis of Bos indicus animals offered a high-concentrate diet. On day 0, 96 noncastrated animals were blocked by initial body weight (400 ± 19.3 kg), randomly allocated to 1 of 24 pens (4 animals/pen), and pens were randomly assigned to receive: 1) control: basal diet composed of whole cottonseed and corn germ as lipid substrates (CONT; n = 6), 2) calcium salts of fatty acids (CSFA) of soybean: CSFA of soybean oil as replacement for whole cottonseed and corn germ (calcium salts of soybean oil [CSSO]; n = 6), 3) CSFA-Blend: CSFA of palm, cottonseed, and soybean oil as replacement for whole cottonseed and corn germ (calcium salts of vegetable oils [CSVO]; n = 6), and 4) Mix: basal diet containing whole cottonseed, corn germ, and CSVO (MIXT; n = 6). Experiment lasted 108 d and performance, ultrasound measurements, as well as carcass characteristics were evaluated. Additionally, meat FA profile, expression of enzymes involved in lipid metabolism, and sensorial analysis were evaluated. No treatment effects were observed on performance variables, ultrasound, and carcass traits (P ≥ 0.22), whereas animals receiving CONT had a greater intake of C10:0, C16:0, C16:1 trans-9, C18:1 cis-9, C18:2, C18:3, total FA, monounsatured FA (MUFA), and polyunsaturated FA (PUFA) vs. CSSO and MIXT (P < 0.05). Conversely, intake ratios of saturated FA (SFA):MUFA and SFA:PUFA were all reduced for CONT vs. other treatments. Meat obtained from CONT animals had greater colorimetric (L*, a*, and b*) values vs. MIXT (P < 0.01). On meat FA profile, CONT increased C18:0 vs. supplementation with calcium salts (P < 0.02) and supplementation with CSSO yielded greater meat concentrations of C18:1 trans-10 and C18:2 CLA intermediates (P < 0.01). Expression of SREBP-1, SCD, and LPL was downregulated for CSSO (P < 0.05). For sensorial analysis, regular flavor was greater (P = 0.01) for CSSO vs. other treatments, but also greater aroma (P = 0.05) vs. CONT and CSVO. In summary, addition of different lipid sources with varying FA profiles into high-concentrate diets did not affect performance and carcass characteristics of B. indicus animals, but supplementation with calcium salts of soybean oil inhibited the mRNA expression of enzymes involved in lipid metabolism, whereas flavor and aroma were positively affected by this lipid source.

Modeling fatty acids for dairy cattle: Models to predict total fatty acid concentration and fatty acid digestion of feedstuffs

Development of predictive models of fatty acid (FA) use by dairy cattle still faces challenges due to high variation in FA composition among feedstuffs and fat supplements. Two meta-analytical studies were carried out to develop empirical models for estimating (1) the total FA concentration of feedstuffs, and (2) the apparent total-tract digestibility of total FA (DCFA_TTa) in dairy cows fed different fat types. In study 1, individual feedstuff data for total crude fat (EE) and FA were taken from commercial laboratories (total of 203 feeds, 1,170,937 samples analyzed for total FA, 1,510,750 samples analyzed for total EE), and data for FA composition were collected from the Cornell Net Carbohydrate and Protein System feed library. All feedstuffs were grouped into 7 classes based on their nutritional components. To predict total FA concentration (% of dry matter) for groups of feeds, the total EE (% of dry matter) was used as an independent variable in the model, and all models were linear. For forages, data were weighted using the inverse of the standard error (SE). Regression coefficients for predicting total FA from EE (% of dry matter) were 0.73 (SE, 0.04), 0.98 (0.02), 0.80 (0.02), 0.61 (0.04), 0.92 (0.03), and 0.93 (0.03), for animal protein, plant protein, energy sources, grain crop forage, by-product feeds, and oilseeds, respectively. The intercepts for plant protein and by-product groups were different from zero and included in the models. As expected, forages had the lowest total FA concentration (slope = 0.57, SE = 0.02). In study 2, data from 30 studies (130 treatment means) that reported DCFA_TTa in dairy cows were used. Data for animal description, diet composition, intakes of total FA, and DCFA_TTa, were collected. Dietary sources of fat were grouped into 11 categories based on their fat characteristic and FA profile. A mixed model including the random effect of study was used to regress digested FA on FA intake with studies weighted according to the inverse of their variance (SE). Dietary intake of extensively saturated triglycerides resulted in markedly lower total FA digestion (DCFA_TTa = 44%) compared with animals consuming unsaturated FA, such as Ca-salts of palm (DCFA_TTa = 76%) and oilseeds (DCFA_TTa = 73%). Cows fed saturated fats had lower total FA digestion among groups, but it was dependent on the FA profile of each fat source. The derived models provide additional insight into FA digestion in ruminants. Predictions of total FA supply and its digestion can be used to adjust fat supplementation programs for dairy cows.

Saturated fat supplemented in the form of triglycerides decreased digestibility and reduced performance of dairy cows as compared to calcium salt of fatty acids

The two most popular rumen-protected fatty acid supplements in dairy cow rations are calcium salts of palm oil fatty acid calcium salts of palm oil fatty acid (CSFA) and prilled saturated fatty acids (SFAs). The objectives of this study were to determine the effects of supplementing SFA in the form of triglycerides (TSFA), as compared to CSFA, on yields, efficiency and diet digestibility in high-yielding dairy cows. Twenty-eight (14 cows in each group) multiparous cows were fed a basal diet supplemented (on DM basis) with either 12 g/kg TSFA (~350 g/cow per day - contained 980 g/kg fat; 882.3 g/kg SFAs) or 14 g/kg CSFA (~440 g/cow per day - contained 800 g/kg fat; 566.4 g/kg SFAs). The supplement amounts in the diet were balanced according to fat content. Rumen samples were taken for measurements of ammonia and volatile fatty acids concentrations, and fecal samples were taken for digestibility measurements. The CSFA cows produced 3% higher milk yields (47.6 v. 46.2 kg/day; P < 0.0001) and 4.7% higher 4% fat-corrected milk (FCM; 44.7 v. 42.7 kg/day; P = 0.02) than the TSFA cows. No difference in milk-fat content was observed, but milk-protein content was higher in the TSFA than CSFA cows. Yields of fat and protein were similar, but lactose yields were higher in TSFA cows. There were no differences in dry matter intake or efficiency calculations between groups. The ruminal ammonia concentrations were similar between groups, whereas acetate concentrations and acetate : propionate ratio were greater for CSFA than TSFA cows. The apparent total-tract digestibility of dry (P < 0.0007) and organic matters (P < 0.0003), fat (P < 0.0001), NDF and ADF (P = 0.02) were lower in the TSFA v. CSFA cows. In conclusion, the CSFA-supplemented cows produced 3% higher milk and 4.7% higher 4% FCM than the TSFA cows. However, TSFA supplementation did not depress milk-protein content. The apparent total-tract digestibility was lower for all dietary components in the TSFA cows, which was probably due to the effects of both degree of saturation and triglyceride form of the TSFA supplement. Considering that diets were balanced according to the fat content of the supplements, the lower yields of milk and FCM observed in the TSFA than CSFA cows were likely due to the lower digestibility of the fat and other nutrients in the TSFA cows, which might have negatively influenced the dietary energy content.

Milk production and nutrient digestibility responses to triglyceride or fatty acid supplements enriched in palmitic acid

The objective of our study was to evaluate the effects of feeding triglyceride and fatty acid (FA) supplements enriched in palmitic acid (PA; C16:0) on production and nutrient digestibility responses of mid-lactation dairy cows. Fifteen Holstein cows (137 ± 49 d in milk) were randomly assigned to a treatment sequence in a 3 × 3 Latin square design. Treatments consisted of a control diet (CON; no added PA) or 1.5% FA added as either a FA supplement (PA-FA) or a triglyceride supplement (PA-TG). The PA supplements replaced soyhulls, and diets were balanced for glycerol content. Periods were 21 d in length with sample and data collection occurring during the final 5 d. Compared with CON, PA treatments increased dry matter (66.5 vs. 63.9%) and neutral detergent fiber (NDF) apparent digestibility (42.0 vs. 38.2%). Although PA treatments tended to increase 18-carbon FA apparent digestibility (79.1 vs. 77.9%), PA treatments decreased 16-carbon (63.1 vs. 75.8%) and total FA (72.0 vs. 76.5%) apparent digestibilities compared with CON. The PA treatments increased milk fat content (3.60 vs. 3.41%), milk fat yield (1.70 vs. 1.60 kg/d), yield of 16-carbon milk FA (570 vs. 471 g/d), 3.5% fat-corrected milk (47.6 vs. 46.5 kg/d), and energy-corrected milk (47.4 vs. 46.6 kg/d) compared with CON. The PA treatments did not affect dry matter intake (28.5 vs. 29.2 kg/d), milk yield (47.0 vs. 47.4 kg/d), milk protein yield (1.42 vs. 1.45 kg/d), milk lactose yield (2.29 vs. 2.31 kg/d), yield of <16-carbon milk FA (360 vs. 370 g/d), yield of >16-carbon milk FA (642 vs. 630 g/d), body weight (720 vs. 723 kg), or body condition score (3.14 vs. 3.23). We did not observe differences in digestibilities of dry matter, NDF, and 18-carbon FA between PA-TG and PA-FA. In contrast, PA-FA increased 16-carbon (68.6 vs. 57.6%) and total FA apparent digestibility (73.8 vs. 70.1%) compared with PA-TG. This resulted in PA-FA supplementation increasing the apparent digestibility of the PA supplement by ∼10 percentage points compared with PA-TG. Compared with PA-TG, PA-FA increased 16-carbon FA intake by 60 g/d, absorbed 16-carbon FA by 86 g/d, and absorbed total FA by 85 g/d. Compared with PA-TG, PA-FA increased dry matter intake (29.1 vs. 27.8 kg/d), yield of 16-carbon milk FA (596 vs. 545 g/d), and tended to increase milk yield (47.6 vs. 46.4 kg/d), milk fat yield (1.70 vs. 1.66 kg/d), and 3.5% fat-corrected milk (48.1 vs. 47.2 kg/d). In conclusion, the production response of dairy cows to PA tended to be greater for a FA supplement compared with a triglyceride supplement. Overall, PA increased NDF digestibility, milk fat yield, energy-corrected milk, and feed efficiency in mid-lactation dairy cows.