Sow Fatty Acid Profile May Alter Weaned Pig Immune Response

In a trial at the Prairie Swine Centre, pigs were subjected to an immune challenge by injecting lipopolysaccharide (LPS), a component of gram-negative bacteria that triggers an immune response.

As a result, weaned pigs produced from sows consuming different fatty acid ratios responded differently to an LPS-induced immune challenge. Researchers concluded that the fatty acid profile of a sow’s diet may affect the response of her offspring to immune challenges that regularly occur at weaning.

This project was designed to determine if feeding sows a diet high in omega-3 fatty acids could improve postweaning performance when pig are challenged with E. coli. Weaned pigs were from sows fed diets with varied omega-6 to omega-3 fatty acid ratios. The diets consisted of a control (tallow-based), 8:1 ratio; plant-based ratios of 10:1, 5:1, and 1:1; and a fish-based, 5:1 ratio.

Sows remained on these diets for two reproductive cycles. Pigs weaned from the second cycle (Day 28 of lactation) were used for the immune challenge. The fatty acid profile of the sow milk was similar to that contained in sow diets, with ratios of 7:1, 7:1, 5:1 1:1 and 3:1 for the diets, respectively.

Weaned pigs were randomly assigned to a saline-injected control group or to an LPS-injected group. Pigs were given six days to acclimate to their new environment prior to the immune challenge. Rectal temperatures were recorded at 0, 1, 2, 3, 4, 5, 6, 12 and 24 hrs. post-injection, and blood samples were collected at 0, 2, 6 and 12 hrs. post-injection for immune analysis.

For three of four immune factors, the effect of challenge, time and challenge by time were significant, indicating that an injection of 0.015 mg/kg bodyweight LPS was effective in generating an immune reaction. 

Diet played a significant role in body temperature, with pigs produced by sows consuming the 1:1 diet having a greater body temperature than those from the control, 10:1 and 5:1 groups. Body temperatures of piglets produced from sows consuming the 5:1 fish-based diet were intermediate.

The diet-by-immune challenge was different for both body temperature and inflammatory response. Pigs from the 1:1 plant-based and 5:1 fish diet groups had a greater inflammatory response to the immune challenge when compared to pigs fed other diets.

Piglets from sows consuming the 1:1 ratio diet were more prone to changes in body temperature in response to the LPS challenge.

Overall, altering the omega-3 to omega-6 fatty acid ratio in sow diets can affect body temperature and immune responses of their offspring when challenged with LPS postweaning.

Researchers: L. Eastwood, P. Leterme and D.A. Beaulieu, Prairie Swine Centre. For more information, contact Beaulieu by phone (306) 667-7442, fax (306) 955-2510 or e-mail: [email protected].

Sow Eating Behavior Studied

Sows are often selected by their body size and placed in gestation groups accordingly. However, Iowa State University (ISU) animal scientists wondered if the speed in which sows ate would be a better guide for determining groups.

The objective of the research was to estimate the range of eating speeds for sows when consuming a predetermined ration. Additionally, researchers studied whether parity affected eating speed and if placing feed on the floor or on a raised ledge affected rate of feed consumption.

To avoid aggression, 11 clinically normal, mixed-parity crossbred sows were purchased from a commercial producer and housed in individual pens at ISU. All sows were fed by hand. The ration was formulated to meet National Research Council (NRC) requirements for each sow at her stage of production. Data was collected on the 4:00 p.m. feeding, when each sow received 2 lb. of feed.

Treatment #1 consisted of floor feeding, with feed placed on a rubber mat in the pen. Treatment #2, the ledge-feeding option, placed the diet on a raised concrete step. Scoring of eating rate was conducted by live observation: one person to one sow.

No appreciable differences were found for sow parity. Parity 1 sows ate quicker (14 minutes) than Parity 2 sows (20 minutes), while Parity 3 sows required 19 minutes and Parity 4 sows took 17 minutes to consume the ration. Regardless of parity, sows ate the feed more quickly when they were fed on the floor vs. on the ledge. The researchers concluded there was no difference in feeding rates between parity of sows when housed individually.

Researchers: Anna Johnson; Kenneth Stalder; Locke Karriker, DVM; Analia Roca; Whitney Holt; and Lori Layman, Iowa State University. For more information, contact Johnson at (515) 294-2098 or e-mail: [email protected].

Specific Plant Extracts Aid Health-Challenged Newly Weaned Pigs

Several plant extracts had beneficial effects on pigs challenged with a pathogenic E. coli bacterium or porcine reproductive and respiratory syndrome (PRRS) virus, in research conducted at the University of Illinois.

Both E. coli diarrhea and PRRS are enormously costly to the pig industry, so their alleviation would substantially reduce production costs. In addition, consumer concerns about residues in animal products and bacterial resistance to antibiotics have prompted the swine industry to seek additional methods of protecting pig health, such as special feed additives. This interest led researchers to explore potential benefits of selected plant extracts.

Two recent studies were conducted to determine whether feeding dietary plant extracts would improve growth performance and disease resistance of newly weaned pigs experimentally infected with a pathogenic E. coli or PRRS virus.

 In the first study, 64 weaned pigs were housed in disease-containment chambers and placed on one of eight treatments in a 2 × 4 factorial arrangement — with or without an F-18 E. coli challenge and four dietary treatments, including:

1.         A nursery basal diet;

2.         Added 10 ppm of capsicum oleoresin, extracted from pepper;

3.         Added 10 ppm of garlicon, extracted from garlic;

4.         Added 10 ppm of turmeric oleoresin, extracted from ginger.

The experimental diets did not contain spray-dried plasma, antibiotics or zinc oxide, and were fed to pigs throughout the experiment. The 15-day experiment was conducted from four days before and 11 days after inoculation.

The results of the first study showed that pigs fed all three plant extracts had lower frequency of diarrhea than pigs fed the control diet, both in the placebo group (7% vs. 20%) and in the E. coli-challenge group (20% vs. 40%). Pigs fed plant extracts were more efficient (40%) in feed use than pigs fed the control diet in the E. coli challenge group. Challenged pigs fed plant extracts had greater ileal villi height (20%) and lower inflammatory mediators, including TNF-α (17%) and haptoglobin (28%) in the blood than pigs fed the control diet.

The experimental design of the second study was similar to the first. Again, 64 weaned pigs were housed in the disease-containment chambers for four weeks and placed on one of eight treatments in a 2 × 4 factorial arrangement: with or without PRRS virus challenge and four dietary treatments. The dietary treatments were the same as in the first study. The experiment was conducted for four weeks — two weeks before and two weeks after inoculation.

 The results of the second study showed that PRRS virus-challenged pigs had poorer growth performance and higher serum viral load and concentrations of inflammatory mediators than pigs without PRRS virus challenge.

Pigs fed the three plant extracts were more efficient in Week 1 (55%) and Week 2 (40%) after PRRS virus challenge than pigs fed the control diet. Challenged pigs fed plant extracts had lower serum viral load (13%) and inflammatory mediators, such as TNF-α (17%) and acute phase proteins (23%), than pigs fed the control diet. 

The first study indicated that feeding plant extracts reduced diarrhea of weaned pigs and decreased inflammatory mediators in E. coli-infected pigs. The second study indicated that feeding plant extracts showed similar beneficial effects, enhanced feed efficiency and reduced serum viral load and inflammatory mediators when pigs were challenged with the PRRS virus.

Results of both trials confirmed the health benefits of added plant extracts.

Researchers: Yanhong Liu, Minho Song, Jeong J. Lee, Tung M. Che, Juliana A. Soares-Almeida, Carol W. Maddox and James E. Pettigrew, University of Illinois-Urbana; David Bravo, Pancosma SA, Geneva, Switzerland; and William G. Van Alstine, Purdue University. Contact Pettigrew at (217) 244-6927 or email: [email protected].

Added Phytase Boosts Phosphorus Digestibility

A project at the University of Illinois to determine the effects of feeding increasing amounts of phytase on energy and phosphorus on various feedstuffs found it did not affect energy digestibility but did improve the digestibility of phosphorous.

This result improves the ability to predict the amount of digestible phosphorus in corn or corn germ at any level of phytase between 0 and 1,500 phytase units.

With this knowledge, pork producers and swine nutritionists will be able to balance swine diets based on digestible phosphorus and greatly decrease the amount of phosphorus required in a diet.

Four corn-based diets, four distiller’s dried grains with solubles (DDGS)-based diets, four high-protein DDGS-based diets, and four corn germ-based diets were formulated. The four diets with each ingredient contained 0, 500, 1,000 or 1,500 phytase units (FTU). A phosphorous-free diet was also formulated to measure endogenous losses of phosphorous. The endogenous losses are those that are secreted by the pig into the intestinal tract and excreted. These losses are needed to create the digestibility values.

A total of 102 pigs weighing 40 lb. were individually housed in metabolism cages equipped with a feeder, a nipple waterer and a screen to collect feces. Pigs were allotted to the diets in a randomized fashion with six replicates per diet.

Phytase did not have an effect on the digestibility of energy. Supplementa­tion of phytase increased the standardized total tract digestibility (STTD) of phosphorous in corn from 40.9% up to 67.5%, 64.5% and 74.9% in the four diets, respectively (Table 1). Phytase tended to increase the STTD of phosphorous in DDGS from 76.9% up to 82.9%, 82.5% and 83.0%.

It increased the STTD of phosphorous in high-protein DDGS from 77.1% up to 88.0%, 84.1% and 86.9%, and increased the STTD of phosphorous in corn germ from 40.7% up to 59.0%, 64.4% and 63.2% in the diets supplemented with 500, 1,000 or 1,500 phytase units/lb. of phytase, respectively.

The results of this trial allow producers and nutritionists to predict the amount of digestible phosphorus in corn and corn germ containing any level of phytase between 0 and 1,500 phytase units.

This work was supported by Pork Checkoff funds.

Researchers: Fernando N. Almeida and Hans H. Stein, University of Illinois. For more information, contact Stein by phone (217) 333-0013, fax (217) 333-7088 or e-mail: [email protected].