Loss of body fat in piglets in spite of gain in live weight

Effects of dietary resveratrol supplementation during gestation and lactation of sows on milk composition of sows and fat metabolism of sucking piglets

The purpose of this article was to investigate the effects of dietary resveratrol supplementation during gestation and lactation of sows on the milk composition of sows and the fat metabolism of sucking piglets. Forty sows were allotted to two experimental treatment groups that included the following: (a) control sows (CON treatment, n = 20) fed with a corn-soybean meal control diet and (b) treatment sows (RES treatment, n = 20) fed with a control diet with addition of 300 mg/kg resveratrol. The results showed that the content of lactose in the colostrum was increased (p < 0.05) and the content of fat in 21-day milk was increased (p < 0.05) by dietary resveratrol supplementation. In the RES treatment group, the concentrations of high-density lipoprotein-cholesterol (HDL-C), low-density lipoprotein-cholesterol (LDL-C), lipase activity and insulin (INS) in plasma of sucking piglets were increased (p < 0.05). In the adipose tissue, the enzyme activities of hormone-sensitive lipase (HSL), acetyl-CoA carboxylase (ACC) and lipoprotein lipase (LPL) increased significantly by RES treatment (p < 0.05), and the mRNA levels of acetyl coenzyme A-alpha (ACCα), LPL, fatty acid transport protein (FATP1) and CCAAT-enhancer-binding protein gene (C/EBPα) were higher in the RES treatment group (p < 0.05). In conclusion, resveratrol supplementation on gestational and lactating sows improved the content of lactose in the colostrum and the content of fat in milk at day 21 of lactation. In addition, resveratrol supplementation on sows increased HDL and LDL in the plasma of piglets. In piglet adipose tissue, the enzyme activity and mRNA level related to lipolysis, fatty acid uptake from circulating triacylglycerols and lipogenesis are partially improved by resveratrol supplementation on sows. These aspects affect fat metabolism in piglets.

Partial optimization of the 5-terminal codon increased a recombination porcine pancreatic lipase (opPPL) expression in Pichia pastoris

Pancreatic lipase plays a key role in intestinal digestion of feed fat, and is often deficient in young animals such as weaning piglets. The objective of this study was to express and characterize a partial codon optimized porcine pancreatic lipase (opPPL). A 537 bp cDNA fragment encoding N-terminus amino acid residue of the mature porcine pancreatic lipase was synthesized according to the codon bias of Pichia pastoris and ligated to the full-length porcine pancreatic lipase cDNA fragment. The codon optimized PPL was cloned into the pPICZαA (Invitrogen, Beijing, China) vector. After the resultant opPPL/pPICZαΑ plasmid was transformed into P.pastoris, the over-expressed extracellular opPPL containing a His-tag to the C terminus was purified using Ni Sepharose affinity column (GE Healthcare, Piscataway, NJ, USA), and was characterized against the native enzyme (commercial PPL from porcine pancreas, Sigma). The opPPL exhibited a molecular mass of approximately 52 kDa, and showed optimal temperature (40°C), optimal pH (8.0), K_m (0.041 mM), and V_max (2.008 µmol.mg protein ⁻¹.min⁻¹) similar to those of the commercial enzyme with p-NPP as the substrate. The recombinant enzyme was stable at 60°C, but lost 80% (P<0.05) of its activity after exposure to heat ≥60°C for 20 min. The codon optimization increased opPPL yield for ca 4 folds (146 mg.L⁻¹ vs 36 mg.L⁻¹) and total enzyme activity increased about 5 folds (1900 IU.L⁻¹ vs 367 IU.L⁻¹) compared with those native naPPL/pPICZαΑ tranformant. Comparison of gene copies and mRNA profiles between the two strains indicated the increased rePPL yields may partly be ascribed to the increased protein translational efficiency after codon optimization. In conclusion, we successfully optimized 5-terminal of porcine pancreatic lipase encoding gene and over-expressed the gene in P. pastoris as an extracellular, functional enzyme. The recombination enzyme demonstrates a potential for future use as an animal feed additive for animal improvement.

Metabolic indicators of nutritional stress are not predictive of abnormal oral behavior in piglets

Belly nosing is an abnormal oral-nasal behavior that can develop to high levels in newly weaned piglets and may signal nutritional need. The effects of feed restriction on both behavior and metabolic serum parameters were examined in 128 weaned piglets. All pigs were fed ad libitum during week 1, and during week 2, half of all pens (N=8) were restricted to 65% of ad libitum intake. Blood samples were collected on days 3 and 10 after weaning and behavior was observed from video recordings on days 5 and 12. Piglets were classified as early 'nosers' or early 'non-nosers' based on their behavior on day 5. Feed restriction resulted in elevated non-esterified fatty acids (NEFA), beta-hydroxybutyrate (BHB) and both lower glucose and a NEFA/glucose ratio, but belly nosing was not affected. Piglets classified as 'nosers' did not have blood profiles indicating they were in greater nutritional need compared to 'non-nosers' in the first week of weaning, nor did they increase belly nosing or other piglet directed behaviors when restricted in week 2. Overall, no associations were found between blood parameters indicative of nutritional stress and belly nosing. This study identifies serum glucose, BHB and NEFA as well as the glucose/NEFA ratio as useful indicators of nutritional stress in newly weaned piglets.

Nitrogen and energy balance in growing mink (Mustela vison) fed different levels of bacterial protein meal produced with natural gas

The objective of this study was to estimate the effect of increasing the dietary content of bacterial protein meal (BPM) on energy and protein metabolism in growing mink kits. Sixteen male mink kits of the standard brown genotype were randomly fed one of four diets: A control (Diet I) based on high-quality fish meal, and three experimental diets in which 20% (Diet II), 40% (Diet III) and 60% (Diet IV) of the digested nitrogen (DN) was replaced with BPM. Nitrogen balance and respiration experiments (indirect calorimetry) were carried out when the animals were approximately 9.5, 14.5, 17.5, 23.5 and 28.5 weeks of age. The apparent digestibility of crude protein and energy decreased significantly with increasing dietary BPM. The retained nitrogen was 0.45, 0.54, 0.52 and 0.40 g/kg0.75 on Diets I, II, III and IV, respectively, the observed differences between diets being non-significant (p = 0.06). Heat production (HE) was between 645 and 665 kJ/kg0.75 on all diets (p = 0.78). Retained energy (RE) was approximately 150-160 kJ/kg0.75 on Diets I to III, whereas it was -11 kJ/kg0.75 on Diet IV, the differences being significant (p< 0.001). A lower feed intake and apparent digestibility of energy caused the negative RE on Diet IV. The amount of HE from oxidation of protein decreased from 32.7% on Diet I to 26.6% on Diet IV, and oxidation of fat increased from 53.8% on Diet I to 63.5% Diet IV. In conclusion, protein and energy metabolism remained unaffected when up to 40% of DN was derived from BPM.

Dietary structured lipids for post-weaning piglets: fat digestibility, nitrogen retention and fatty acid profiles of tissues

In four groups of post-weaning piglets the effects of triacylglycerol structure and fatty acid profiles of four dietary fats on apparent faecal nutrient digestibility, nitrogen retention and fatty acid profiles of platelet and erythrocyte membranes, liver, adipose tissue and skeletal muscle were examined. Dietary fats included as 10% (w/w) of the diets were two structured fats of rapeseed oil interesterified with tridecanoin (R1) or coconut oil (R2), respectively, one mixture of rapeseed oil and coconut oil (R3) and rapeseed oil as control (R4). Faeces and urine from piglets weaned at 28 days of age were collected quantitatively during three periods each of 5 days, in which the piglets were kept in metabolism cages for measurement of apparent faecal nutrient and energy digestibility and nitrogen retention. Apparent faecal fat digestibilities were significantly improved in groups fed interesterified fats or the physical mixtures (R1, R2 and R3) compared with rapeseed oil (R4). Apparent faecal nitrogen digestibility and retention were similar in all four groups in the three periods, but increased with time. Apparent faecal fat digestibilities were significantly improved from the first to the third week in the groups R1 and R2. Fatty acid profiles in platelet and erythrocyte membranes and in tissues reflected the fatty acid profile of the dietary fat, except for medium-chain fatty acids, which were only found in low proportions, indicating that 10:0 was mainly used as an energy source.

Exocrine pancreatic secretion is stimulated in piglets fed fish oil compared with those fed coconut oil or lard

An experiment was conducted to study the effect of feeding diets containing fat sources with different fatty acid composition (fish oil, coconut oil or lard, 10 g/100 g diet) on exocrine pancreatic secretion in piglets after weaning. A total of 16 barrows were weaned at 4 wk of age; 3 d later, they were surgically fitted with a catheter in the pancreatic duct for continuous collection of pancreatic juice. Collections of pancreatic juice were made every other day starting 4 d postsurgically. Piglets fed the fish oil diet secreted a significantly greater volume of pancreatic juice than piglets fed the coconut oil or lard diets. The output [U/(h. kg(0.75))] of lipase was higher in piglets fed fish oil than in piglets fed lard or coconut oil. The output of colipase was greater in piglets fed fish oil and coconut oil than in those fed lard. The dietary treatments did not affect the output of carboxylester hydrolase. The output of trypsin was significantly lower in piglets fed lard than in piglets fed fish oil or coconut oil diets and the output of carboxypeptidase B was greater in those fed the fish oil diet. Protein, chymotrypsin, carboxypeptidase A, elastase and amylase outputs did not differ among the dietary treatment groups. The apparent digestibilities of nutrients and energy were measured in feces and did not differ among groups. Thus, the greater output of lipase in fish oil-fed piglets did not result in a greater digestibility of fat in this diet.

Estimation of net nutrient oxidation and lipogenesis in growing pigs

Data from previous series of trials were reevaluated in order to quantify the net nutrient oxidation and lipogenesis by combining data from balance experiments and indirect calorimetry measurements. The experiments were carried out with eight castrated males of Danish Landrace measured individually from 30 to 100 kg BW. All pigs were fed alternately on high feeding level, near ad libitum and on low feeding level, near maintenance. Oxidation of carbohydrate (OXCHO) and fat (OXF) was calculated from gas exchange measurements. On high feeding level the contribution from OXCHO and OXF to the total heat production was 55 and 30%, respectively, at 30 kg BW and fairly constant from 60 kg BW with OXCHO around 80% and no net OXF. At low feeding level the contribution from OXCHO and OXF was 28 and 63%, respectively, at 30 kg BW, increasing to 52% for OXCHO and decreasing to 37% for OXF at 95 kg BW. The lipogenesis on high feeding level increased from 2.4 to 11.9 MJ/d, while on low feeding level it increased from 2.5 to 3.6 MJ/d at 30 to 95 kg BW. The intake of carbohydrate was too low to cover energy requirement by OXCHO on low feeding level and in the first periods on high feeding level and OXF occurred. In spite of a deficit of carbohydrate for oxidation a part of carbohydrate (2.6 MJ/d, approximately 150 g/d) was used for fat synthesis, indicating an importance of lipogenesis in growing pigs.

Pattern of protein retention in growing boars of different breeds, and estimation of maximum protein retention

Protein and energy metabolism in boars of different breeds, 10 each of Hampshire, Duroc and Danish Landrace was measured in balance and respiration experiments by means of indirect calorimetry in an open-air circulation system. Measurements were performed in four periods (Period I-IV) covering the body weight range from 25 to 100 kg. In order to achieve maximum protein retention (RP) a daily intake of digestible protein > 12 g/kg0.75 and metabolisable energy > 1100 kJ/kg0.75 was assumed to be necessary. Protein retention of Danish Landrace boars was inferior to that of Hampshire and Duroc boars in Periods III and IV, and therefore, 55 measurements on Hampshire and Duroc boars fulfilling the chosen criteria for digested protein and ME intake were used for calculation of maximum protein retention, giving the following significant quadratic relationship: RP [g/d] = 11.43.W0.75-0.144.W1.50 (n = 55, RSD = 15.2, CV = 9.2%, R2 = 0.851) with a summit of 227 g/d at 135 kg BW. In Period I, when BW was below 30 kg, 12 measurements fulfilled the chosen criterion for digested protein but not for ME, and these data were used comparatively. Protein retention of boars with a low ME intake in Period I was significantly below that of boars with a high ME intake (93 g/d vs. 107 g/d; P = 0.02). In summary, the present data have shown that boars of high genetic potential have capacity for maximum protein retention of about 230 g/d, and that there was a significant quadratic relationship between protein retention and metabolic body weight, indicating that maximum protein retention was not reached until 135 kg BW. Differences in capacity for protein retention were recorded between boars of different breeds, with Duroc and Hampshire boars being superior to Danish Landrace boars. Additionally, the crucial importance of a sufficient ME supply early in the growth period was underscored by a lower protein accretion rate of boars given a daily ME supply below 1100 kJ ME/kg0.75 at an approximate BW of 25 kg.

Heat production and substrate oxidation in rats fed at maintenance level and during fasting

A total of 36 Wistar rats were fed a commercial diet to a stipulated live weight of 75 g (Group A), 100 g (Group B) and 225 g (Group C). All rats were measured in energy balance experiments, in which the animals were fed near maintenance level, followed by a period of fasting with measurements of the gas exchange. The rats in Group A, B and C were fasted for 2, 3 and 4 days, respectively. The minimum heat production on the last day of fasting for all groups was proportional to metabolic body weight (kg0.75) with a regression: heat production, kJ day-1 = 321 x kg0.75 (R2 = 0.994). In rats fed near maintenance level, heat production was provided by oxidation of carbohydrates in 80-85%, oxidation of protein was 10-15%, while oxidation of fat contributed less than 10%. It is suggested that in the fasting period, the contribution to the total heat production from oxidized carbohydrate and fat depended on the size of the fat depots, a large fat depot giving rise to fat oxidation. On the last day of fasting, 24, 51 and 90% of the total heat originated from fat oxidation in Group A, B and C, respectively.

Quantitative partition of protein, carbohydrate and fat pools in growing pigs

A model combining data from balance experiments with data from oxidation of nutrients demonstrating the pools of protein, carbohydrate and fat and their partition in the body was presented. Data from more than 200 experiments with growing pigs were used to fill up the "black boxes" in the model and to discuss the pattern between catabolic and anabolic processes of the different nutrients. With a ME-intake of 1.3 MJ/kg0.75 the proportion of retained protein from the protein pool varied from 50 to 75% depending on the age of animals and the protein quality. At a low protein intake and ME of 0.6 MJ/kg0.75 the utilization of protein was reduced to about 25% as a substantial part of the protein pool was oxidized. The carbohydrate group from the protein sources constituted less than 5% of the carbohydrate pool. The oxidation of carbohydrates was between 50-75% of the pool in all experiments, while the rest was used for lipogenesis. Even on a low feeding level the pattern occurred indicating a requirement for specific substances formed in the body. Lipogenesis constituted 46-96% of the fat pool depending of the amount on digested fat in the different experiments. No oxidation of fat was observed in experiments with pigs (30-90 kg LW) on a high feeding level in spite of the broad variation in the amount of digested fat, indicating a complete storage of the fat pool into body fat. In experiments with piglets (3-9 kg LW) on the same energy intake fat oxidation of about 30% occurred, probably caused by the high energy requirement of the piglets.(ABSTRACT TRUNCATED AT 250 WORDS)