Lipid Use and Metabolic Disorders

1. Lipid Use and Metabolic Disorders

2. Fatty Acid Profile • Major fatty acids in feed fats • C16:0 Palmitic acid • C16:1 Palmitoleic acid • C18:0 Stearic acid • C18:1 Oleic acid • C18:2 Linoleic acid • C18:3 Linolenic acid • Unsaturated:saturated ratio = • C16:1 + C18:1 + C18:2 + C18:3 • C16:0 + C18:0

3. Types of Feed Fats and Oils • Oils • Vegetable oils • Soapstocks = FA + salt ion (Na, K) • Fats • Tallow, lard • Choice white grease • Restaurant grease • Blends • Oils + fats

4. Fat Sources • Oil sources • Soapstock • Vegetable oil • Restaurant grease • Fat sources • Pig and cattle tissues from: • Slaughter plants, lockers • Grocery stores • Deadstock Age of oil/heat damage? % free fatty acids? Hydrogenated oil (trans fatty acids)? Variation due to • U:S ratio • % free-fatty acids • Others

5. Age and Energy Values (Poults) Fat digestibility increases with age ME (kcal/lb) Age (weeks)

6. U:S Ratio and Energy Values 1) Saturated FA are not digested as well as unsaturated FA ME (kcal/lb) Unsaturated:Saturated ratio

7. U:S Ratio and Energy Values ME (kcal/lb) Old Young • Saturated FA are not digested as well as unsaturated FA • The situation is worse for young animals Wiseman et al. (1991) Unsaturated:Saturated Ratio

8. Free Fatty Acids and Energy Values Old Young ME (kcal/lb) 1) FFA are not digested as well as TGs 2) The problem is worse in young animals 0 10 20 30 40 50 60 70 80 90 100 Free Fatty Acids (%)

9. Heat Damage and Energy Values ME (kcal/lb) Heating time at 360°F (hrs) Heat damage progressively reduces the feeding value of restaurant grease

10. Fat Deficiency • Carnivore diets with under 5% total fat can induce essential fatty acid deficiencies • Symptoms include dull hair coat, reproductive failure (testicular underdevelopment, anestrus, and lack of libido), and dry, scaly skin • Adding essential fatty acids to diets with over 15% total fat not beneficial • Essential fatty acids only required at ~1% of diet • Birds on deficient diet show poor feathering • Difficult to create deficiency in ruminants or cecal fermenters (caprophagy) • Microbes synthesize adequate amounts of fats

11. Lipid Supplementation of Diets • Advantages • Increases energy density • Low heat increment (ruminants) • Decreases dust • Increases pellet quality • Lubricates machinery • Disadvantages • Decreases milk fat (ruminants)

12. Tolerance of Fats in Diets • Horses can tolerate fat levels up to 20% of their diet • Dogs can tolerate up to 40% fat in diet • Ruminants can only tolerate 7-8% fat in diet, because more than that adversely affects microbes and decreases feed consumption and fiber digestion • Can be fed more if fed as bypass fat • EXCEPTION: Newborn ruminants can be fed over 30% fat diets - essentially a monogastric species

13. Over-feeding Fats • Overfeeding fats leads to more fat deposition than overfeeding carbohydrates • ~95% of extra energy deposited as fat compared to 75% for carbohydrate overfeeding • Shorter chain fatty acids (not included in lipoproteins and chylomicrons) have effects closer to carbohydrates • Induction of fatty liver • Hyperplasia and hypertrophy of pancreatic islets cells • Early indications of diabetes mellitus • Impaired memory and learning functions!!!

14. Impaired Lipid Digestion or Absorption • Pancreatic disorders • Liver disorders • Small intestinal problems • Causes steatorrhea • Excessive fat in feces (grey color, greasy appearance) • Most frequently seen in companion animals

15. CLA – Conjugated Linoleic Acid • Related to linoleic acid (18:2) • CLA is 18:4 • Produced by rumen organisms • Cellulolytic bacteria • Source • Ruminant products • Meat • Milk

16. Conjugated Linoleic Acid

17. CLA - Conjugated Linoleic Acid • Naturally trans double bond • ONLY made by microbes • CLA levels are higher in grass fed ruminants (and kangaroos or other foregut fermenters) • Not in hindgut fermenters!! • Wide range of proposed benefits • Lean muscle gain, decreased fat deposition, inhibitory for inflammatory mediators and tumors • Cannot be utilized by liver enzyme D-6-D in prostaglandin synthesis • Block prostaglandin production and reduce inflammatory responses

18. Metabolic Disorders • Impairment of liver function can alter lipid metabolism • Infectious disease, genetic disorders • Other drugs or compounds • Large number of metabolic disorders associated with lipid metabolism • Genetic: usually appear at birth, fatal • Tay-Sachs is ONE example

19. Tay-Sachs • Autosomal recessive trait • Accumulation of gangliosides (fatty acid derivatives) in CNS neurons • Lack enzyme that breaks down lipids • Gangliosides accumulate, destroy function of neurons, and eventually destroy neurons themselves

20. Infantile Tay-Sachs • Most common variant • Appear normal at first, but by 6 months of age affected infants become blind, deaf, unable to swallow, muscles atrophy and eventually become paralyzed • Death before age 4 in most cases • Juvenile onset and adult onset variants also exist

21. Metabolic Disorder – Fatty Liver Negative energy balance Rapid mobilization of adipose tissue Liver can not efficiently utilize fats Liver stores fat, produces ketones

22. Hyperlipemia • Horses and ponies, llamas and alpacas • Similar to ketosis in cattle • Mobilization of body fats and incomplete oxidation leading to excess ketones in blood • Occurs with poor feed intake in conjunction with high energy demand (pregnancy, lactation, stress) • Higher frequency in obese animals

23. Fatty Liver • Consequences • Impaired liver function • Increased incidence of disease • Decreased fertility • Prevention • Increase diet energy density prior to parturition • Do not over-condition animals prior to parturition

24. Ketosis/Pregnancy Toxemia • Adipose response to low blood glucose Free fatty acids (FFA) released Low blood glucose Fat reserves mobilized Partial oxidation of FFA to ketone bodies Liver uptake of FFA

25. Ketosis • Dairy cows • Pregnant ewes • Occurs most often following calving • Increased glucose demands to support lactation • Body fat is mobilized to meet energy demands, but TCA cycle ‘backs up’ • Over conditioned cows • Last third of gestation • Fetus takes up space and reduces capacity of intestine • Caused by inadequate energy intake • Mortality can be as high as 80% • Twin lamb disease

26. Acetone Ethyl Alcohol

27. High-Protein, High-Fat Diets • Used as a dieting tool by some people • Relies on extremely low intakes of carbohydrates – very little glucose absorbed • Use fat and protein as primary energy sources • Monitor ketones – when ketones elevated enough, diet is “successful” • Why does this work?? • What are consequences??

28. Fat Replacers • Simpless: • Protein based fat replacement • Made of egg white, milk protein or whey • Not suitable for baking or frying • Olestra: • Made from sucrose and fatty acids • 1 oz bag of chips: zero fat and 70 kcal • Regular bag of chips: 10 gms fat and 150 kcal • Side effects: abdominal cramps and diarrhea, fecal incontinence