Effect of inclusion of fermentable carbohydrates in the diet on fermentation end-product profile in feces of weanling piglets

An in vivo experiment was conducted to monitor the changes in fermentation end products in the feces of weaning piglets due to the inclusion of selected fermentable carbohydrates in the diet. The experiment involved 3 groups of 16 piglets each. Specially raised piglets (neither antibiotics nor creep feeding) were weaned abruptly at 4 wk of age. The piglets were offered 1 of 2 dietary treatments [a control diet (CON), or a fermentable carbohydrate-enriched diet (CHO)] and were subjected to 1 of the 2 fasting treatments (fasting for 2 d at the beginning of the experimental period or nonfasting). Fecal samples were collected per rectum every day during the experimental period. Piglets were slaughtered at the end of the 10-d experimental period, and digesta samples were collected from different parts of the gastrointestinal tract (GIT): the first half of the small intestine, the second half of the small intestine, the cecum, and colon. The DM, VFA profile, and ammonia concentrations were analyzed from the fecal and digesta samples. Daily feed intake was also recorded. There was no difference in concentrations of VFA in feces between the treatment groups. Ammonia concentration was lower (P < 0.05) in piglets fed the CHO diet compared with those fed the CON diet in both feces and digesta from different parts of GIT. Fasting had no effect on fermentation end products in feces. This study demonstrated that the inclusion of fermentable carbohydrates in weanling diets reduces protein fermentation along the GIT and also reduced the fecal concentration of ammonia.

Use of the in vitro cumulative gas production technique for pigs: An examination of alterations in fermentation products and substrate losses at various time points1

An experiment was conducted to examine changes in VFA and ammonia concentrations at different time points using 4 fermentable carbohydrate-rich feed ingredients as substrates and feces of unweaned piglets as inoculum. Fecal inoculum was collected, pooled, and mixed from 9 specially raised (no creep feed or antibiotics) crossbred piglets at 3 wk of age. Inulin, lactulose, molasses-free sugar beet pulp, and wheat starch were used as substrates and were fermented in vitro for 72 h (3 replicates per substrate). Cumulative gas production was measured as an indicator of the kinetics of fermentation. In addition, 3 bottles of substrate per time point with similar contents (amounts of substrate, inoculum, and media) were incubated but were allowed to release their gas throughout incubation. For these latter bottles, fermentation fluid was sampled at incubation time points including every hour between 1 and 24 h and at 48 h, and fermentation end products (VFA, lactate, and ammonia) and OM disappearance were measured. Dry matter and ash were analyzed from the postfermentative samples. The pH of the contents from these bottles was also recorded. The correlation in time between fermentation end products and cumulative gas produced was determined. The results showed that the prolongation of fermentation to 72 h, especially in the case of fast-fermenting inulin and lactulose, may lead to a different end product profile (P < 0.001) compared with the profile observed at the time at which most of the substrate has disappeared. Therefore, we concluded that the fermentation product profile at the end of in vitro fermentation at a specific time point cannot be used to compare fermentability of carbohydrate sources with different fermentation kinetics in terms of gas production.

Apparent ileal and total-tract nutrient digestion by pigs as affected by dietary nondigestible oligosaccharides

The effects of two types of nondigestible oligosaccharides (NDO), fructooligosaccharides (FOS), and transgalactooligosaccharides (TOS) were studied on growing and weanling pigs' nutrient digestion. Dietary NDO were included at the expense of purified cellulose. Twenty-five 57-d-old growing pigs, averaging 15.9+/-.6 kg on d 0 of the experiment, were fed a corn-based control diet or the control with 6.8 or 13.5 g of FOS/kg or 4.0 or 8.0 g of TOS/kg (five pigs per diet). Feces were collected on d 28 to 32, and small-intestinal digesta were collected (slaughter technique) on d 42 to 47 of the experiment. Feeds, feces, and digesta were analyzed for DM, inorganic matter, CP, ether extract, and crude fiber. Dietary NDO did not significantly affect apparent fecal and small intestinal digestion of nutrients in growing pigs. After being fed a NDO-free diet through d 10 after weaning, 38-d-old weanling pigs (n = 20), averaging 10.4+/-.8 kg on d 0 of the experiment, were fed a control diet (based on cornstarch, casein, and oat husk meal) or the control with 10 or 40 g of FOS or TOS/kg (four pigs per diet). Feces and urine were collected on d 13 to 17, and ileal digesta were collected via a postvalve T-cecum cannula on d 33 to 37 of the experiment. Feeds, feces, and digesta were analyzed for DM, inorganic matter, CP, ether extract, starch, NDF, ADF, ADL, Ca, P, Mg, Fe, Cu, and Zn. Nonstarch neutral-detergent soluble carbohydrates (NNSC) completed the mass balance for the carbohydrates. Urine was analyzed for N and minerals. The apparent fecal digestion of NNSC increased in the NDO-supplemented diets. The TOS-fed pigs tended (P<.10) to have a higher apparent fecal digestion of CP than the FOS-fed and control pigs but excreted more N via the urine (P<.01). Nitrogen and mineral balances were not affected. The FOS was nearly completely degraded prececally. Mean fiber digestion was lower at the fecal compared with the ileal level, as was the extent of NDO effects. This indicates that fiber digestion requires more than 2 wk to adapt to dietary NDO. Apparent ileal digestion of hemicellulose increased for the NDO-supplemented diets (P<.05), but that of NNSC decreased (P<.001). Thus, under the well-controlled conditions of this experiment, dietary NDO hardly affected nutrient digestion in well-kept growing and weanling pigs. However, digestion of dietary nonstarch carbohydrates may be affected.

The energetic value of nonstarch polysaccharides in relation to physical activity in group-housed, growing pigs

The dose response effect of dietary nonstarch polysaccharide (NSP) content on physical activity in relation to metabolic rate in pigs was studied. Twelve clusters of 14 pigs (50-kg castrated males) were fed one of four diets, similar in composition, except for the starch and NSP content. The difference in starch and NSP ratio was created by exchanging sugar beet pulp silage (SBPS) for tapioca. On a DM basis, diets contained 0, 5, 10, or 15% SBPS. Pigs were housed in groups and fed at 2.5 times the maintenance energy requirements. Nitrogen and energy balances were measured per cluster during a 7-d experimental period, which was preceded by a 2-wk adaptation period. Dietary composition did not affect ADG. Metabolizability decreased with increasing dietary SBPS content (P < .01). Heat production as well as energy retention were unaffected by the exchange of starch for NSP (P > .1). However, dietary composition affected energy expenditure on physical activity (P < .10). Pigs were more quiet when dietary NSP content increased. Based on heat production data and on apparent digestibility of crude protein, crude fat, and NSP, the estimated net energy value of fermented NSP was 14.8 kJ/g. This relatively high energy value of fermented NSP was mainly related to the lowered energy expenditure for physical activity, 3.9 kJ/g of fermented NSP. The present study demonstrated that the lower energetic utilization of fermented NSP compared with that of starch can be fully compensated in pigs by reducing their physical activity. Thus, energy evaluation systems should account for systematic dietary influences on physical activity.

Evaluation of a model integrating protein and energy metabolism in preruminant calves

In a companion paper, a mechanistic model is described, integrating protein and energy metabolism in preruminant calves of 80-240 kg live weight. The model simulates the partitioning of nutrients from ingestion through intermediary metabolism to growth, consisting of accretions of protein, fat, ash and water. The model also includes a routine to check possible dietary amino acid imbalance and can be used to predict amino acid requirements. This paper describes a sensitivity and behavioral analysis of the model, as well as tests against independent data. Increasing the carbohydrate:fat ratio at equal gross energy intakes leads to higher simulated protein- and lower simulated fat-deposition rates. Simulation of two experiments, not used for the development of the model, showed that rates of gain of live weight, protein and fat were predicted satisfactorily. The representation of protein turnover enables the investigation of the quantitative importance of hide, bone and visceral protein in protein and energy metabolism. The model is highly sensitive to 25% changes in kinetic parameters describing muscle protein synthesis and amino acid oxidation. Comparing simulated with experimentally derived amino acid requirements shows agreement for most amino acids for calves of approximately 90 kg live weight. For calves of approximately 230 kg live weight, however, lower requirements for lysine and for methionine+cystine are suggested by the model. More attention has to be paid to the inevitable oxidative losses of amino acids. It is concluded that the model provides a useful tool for the development of feeding strategies for preruminant calves in this weight range.

Effect of protein and protein-free energy intake on protein and fat deposition rates in preruminant calves of 80 to 240 kg live weight

Two experiments were conducted to quantify the effects of protein intake on protein and fat deposition rates at two protein-free, energy intake levels in 90 preruminant Holstein Friesian x Dutch Friesian calves. The two experiments were similar in design, but were performed in two different weight ranges: 80 to 160 kg BW and 160 to 240 kg BW in Exp. 1 and 2, respectively. In each experiment, calves were allocated to either an initial slaughter group or to one of 12 treatments (three calves per treatment), which consisted of six protein intake levels at each of two protein-free energy intake levels. Calves were slaughtered and analyzed for body composition when they had reached the target weight. A balance study was conducted when calves reached 120 and 200 kg BW in Exp. 1 and 2, respectively. Protein digestibility increased with increasing protein intake in both experiments (P < .001). Average daily gain of the empty body varied between 640 and 1,340 g/d and between 420 and 1,370 g/d in Exp. 1 and 2, respectively, and was affected by protein (P < .001) and protein-free energy intake (P < .001). The calves responded to increased protein intake by increasing their protein (P < .001) and fat (P < .01) deposition rates. Maximum protein deposition was reached in the second experiment at 244 g/d. Extra protein-free energy intake resulted mainly in extra fat deposition (P < .001), but also increased the protein deposition (P < .01), even at low protein intake levels. In both experiments, the response of protein deposition rate to increased protein intakes was low: about 30% of the extra ingested protein was deposited. These results clearly demonstrate a low priority for partitioning dietary protein into protein gain in these calves.

Performance and body composition of finishing gilts (45 to 85 kilograms) as affected by energy intake and nutrition in earlier life: I. Growth of the body and body components

Forty-eight commercial hybrid gilts were used to determine the effects of energy intake from 20 to 45 kg on the relationship between energy intake and weight gain of the body and body components from 45 to 85 kg. Two groups of 24 gilts received a single diet either at 2.2 (restricted) or 3.7 (control) times maintenance (M) from 20 to 45 kg. From 45 to 85 kg the pigs were fed the same diet at one of six intake levels (1.7, 2.2, 2.7, 3.2, or 3.7 x M, or ad libitum). At 85 kg, the gilts were dissected into organs, lean tissue (trimmed major joints), and other carcass parts (fat fraction). In the restricted gilts, body and lean tissue gain between 45 and 85 kg increased curvilinearly with increasing energy intake from 432 to 1,412 g/d and from 228 to 507 g/d, respectively. In the control gilts, body and lean tissue gain increased from 394 to 1,201 g/d and from 238 to 508 g/d, respectively. The percentage of lean tissue in the carcass decreased curvilinearly with increasing energy intake from 62.9 to 56.5%, and from 62.5 to 53.9% in the restricted and control gilts, respectively. The restricted gilts gained on average 140 g/d faster (P < .001) and their carcass lean tissue content at slaughter was approximately 3% higher (P < .001). These differences increased with increasing energy level between 45 and 85 kg. The increased gain was largely the result of an increase in organ growth and gut contents and was only evident up to 65 kg. The higher lean content at 85 kg in previously restricted gilts was not the result of compensation in lean gain but was already present at the end of the restriction phase at 45 kg.

Energy metabolism in young pigs as affected by mixing

The effect of mixing on energy metabolism was studied in 8-wk-old pigs. In each of two trials, two clusters of 20 pigs (two litters of 10 pigs) were randomly assigned to one of two treatments: control or mixing. Each cluster was housed in two pens. In each trial, after a preliminary period od 2 wk, the two litters within the mixing treatment were mixed at the start of a 2-wk experimental period. During mixing, the five heaviest pigs of each litter were put together in one pen, and the five lightest pigs of each litter were put together in the other pen. In the control treatment, the social structure of both litters in one climatic chamber was not altered. After mixing, a short-term effect on total heat production and activity-related heat production was present. Both were increased (P < .01) only during the 1st h after mixing. Only 57.3% of this increased total heat production was caused by an increased activity. However, no long-term effects of mixing on energy partitioning were present during the total experimental period. The absence of a long-term mixing effect might be caused by the optimal conditions at the moment of mixing. In the preliminary period the transposition of GE into ME increased 1.3% (P < .05), and ME for maintenance decreased 80 kJ.kg(-.75).d(-1) (P < .01) between wk 1 and 2. These large alterations in energy metabolism are probably a carry-over effect of the transportation of the pigs and (or) the changes in housing environment.

Effects of energy source in the diet on reproductive hormones and insulin during lactation and subsequent estrus in multiparous sows

Two experiments were performed. The first experiment was done to study the effects of dietary energy source on plasma insulin concentration using five gilts in a Latin square design with two diets over two periods. The diets contained either 200 g/kg of cornstarch (Starch) or soybean oil (Fat) as energy sources. Results indicate that insulin response was greater in the Starch-fed than in the Fat-fed gilts. A second experiment was performed in which 18 multiparous sows were fed one of the two experimental diets from farrowing until slaughter at d 35 of subsequent pregnancy. All sows nursed nine pigs. Blood samples were taken from a permanent jugular vein catheter every 12 min during a 12-h period on d 109 +/- 1 of pregnancy, on d 7 +/- 1, 14 +/- 1, and 21 +/- 1 of lactation, and on the day of weaning ( d 22 +/- 1). From 48 h after weaning, blood samples were taken every 4 h until 24 h after ovulation. After that, blood samples were taken at 12-h intervals until d 10 after ovulation. Differences between diets in insulin response were not significant. In Starch-fed sows, LH pulsatility at d 7 of lactation was greater (P < .05), the preovulatory LH surge was greater ( P < .05), and progesterone production was greater (P < .05) from 108 h until 256 h after the LH surge than in the Fat-fed sows. Results indicate that feeding Starch-rich diets to multiparous sows compared with Fat-rich diets, on an isocaloric basis, increases LH pulsatility during early lactation, the preovulatory LH surge, and progesterone production after the LH surge.

Passage rate and total clearance rate from the rumen of cows fed on grass silages differing in cell-wall content

Four non-lactating, rumen-fistulated cows were fed ad lib. on two grass silages (first cut (FC) and second cut (SC) harvested at different growth stages, resulting in different crude-protein (CP) and neutral-detergent-fibre (NDF) contents (FC, 152g CP/kg, 515g NDF/kg and SC, 210g CP/kg, 442g NDF/kg). Voluntary intake and rumen contents, total as well as organic matter were higher for silage FC. Fractional passage rate from the rumen, calculated from the logarithmic decline in Cr-NDF rumen pool, was higher for silage FC (0.0395/h and 0.0446/h for silages SC and FC respectively). When fractional passage rates from the rumen were calculated by dividing the intake of indigestible organic matter by the mean rumen pool of this fraction, the same differences between silages were found, although the actual levels were much lower (0.0258/h and 0.0300/h for silages SC and FC respectively). The results from the present experiment suggest that disappearance rate from the rumen of particles with a size between 1.25 and 0.071 mm is the rate-limiting step in the control of rumen fill.

Amino acid composition of growing pigs is affected by protein and energy intake

Ninety-five female pigs from 20 to 45 kg body weight were used to elucidate the effects of energy and protein intake on the amino acid composition of the protein in the carcass, organs and empty body of growing pigs. In a 2 x 15 factorial arrangement, protein intake ranged from 127 to 350 g/d in 15 graduated steps; and the digestible energy allowances were 15.8 and 18.8 MJ/d. Whole-body amino acid contents (g/16 g nitrogen) were (means +/- SEM) lysine 6.64 +/- 0.028, methionine 2.11 +/- 0.012; threonine 3.62 +/- 0.016 and total essential amino acids 42.8 +/- 0.16. The organ fraction contained 14.8 and 15.8% (SEM 0.13) of whole-body protein at the low and high energy levels, respectively. The concentrations of essential amino acids were 41.8 +/- 0.19 and 48.4 +/- 0.13 g/16 g nitrogen in the carcass and organs, respectively. Concentrations of a number of amino acids (in carcass, organ and whole-body protein and in protein deposited between 20 and 45 kg, were affected by protein and/or energy intake. The amino acid pattern of the newly deposited protein was slightly different from that of the empty body protein. The changes in amino acid contents were presumably the result of effects of protein and energy intake on the proportions of muscle and non-muscle carcass tissues and on relative weights of blood and viscera. Consequences of these changes for the amino acid requirements are discussed.

On the fluorimetric determination of oestriol in pregnancy urines after thin layer chromatography

An improved method is described for the determination of oestriol concentrations in urines of pregnant women. Oestriol is detected as a derivate of 1-dimethylaminonaphtalene-5-sulphonylchloride (DANSYLchloride). The method has the following characteristics: 1. The recovery of oestriol-16-glucuronide is 94%. 2. For the interpretation of the results obtained with this method mean values and 95% probability bounds of urinary oestriol excretion for each week of the last three months of pregnancy are given. (e.g. 49--125 mumol/24 h at 32 weeks of gestation, 108--238 mumol/24 h at 40 weeks). 3. The coefficient of variation of the method is 4% (from day to day). 4. The lowest detectable concentration is 3 mumol/l. 5. Influence of glucose can be eliminated. 6. Other urinary compounds have no influence on the determination.