Chinese herbal feed additives for piglets: dose and days
Chinese herbal feed additives for piglets do work, but only inside a narrow window, and this trial maps the edges of it. A fermented blend of 18 herbs plus probiotics lifted average daily gain in piglets from 309 g to 402 g and average daily feed intake in piglets from 489 g to 604 g. The best result came at 0.2 percent held for a full 28 days. Push the same blend to 0.4 percent for 28 days and the pigs finish lighter than pigs that got nothing at all.
The problem this study was built around
Weaning splits a piglet in two directions at once. Feed intake drops. The gut barrier gets leaky. Whatever is in the environment gets a better shot at the animal. For years the cheap fix was a low-level antimicrobial mixed into the feed, and that fix has mostly been taken away.
Plant preparations became the obvious candidate to fill the space, and the hunt for antibiotic-free feed additives for piglets turned into the busiest line of work in pig nutrition. No residue, low resistance risk, and a chemistry that is broad rather than narrow. Polysaccharides, flavonoids, saponins, terpenoids, essential oils, alkaloids, organic acids. Different fractions push on different things, which is exactly why a blend is interesting and exactly why a blend is hard to recommend.
Hard to recommend because the trials mostly do not answer the two questions that matter commercially. What rate? For how many days? Most published work picks one rate, runs it for one period, and reports a positive result. So a producer reading the literature learns that the category works and still has no number to put in the diet.
That is the gap this study went after. Three rates, two feeding periods, run as a proper factorial so the two factors could be pulled apart, plus an untreated pen for reference.
What was actually tested
Seven groups. 210 piglets, weaned, 28 days old give or take a day. Three pens per group, ten pigs to a pen. Three days of adaptation, then 28 days of trial.
| Parameter | Detail |
| Animals | 210 healthy piglets, 28 plus or minus 1 days old, weaned, equal sex ratio |
| Groups | 7 (1 untreated control plus 6 treatment groups) |
| Replicates | 3 pens per group, 10 pigs per pen |
| Adaptation | 3 days on the basal diet |
| Trial length | 28 days of feeding |
| Factor 1 | Additive concentration: 0.2, 0.3, 0.4 percent |
| Factor 2 | Feeding duration: 14 days or 28 days |
| Groups I to III | Additive for days 4 to 17, then basal diet for days 18 to 31 |
| Groups IV to VI | Additive for the full 28 days |
| Housing | Ad libitum feed and water, routine vaccination, scheduled disinfection |
| Measured | ADG, ADFI, feed to gain, apparent digestibility, serum biochemistry, immunoglobulins and cytokines, antioxidant indices, faecal 16S rRNA sequencing of the microbiota |
| Group | Concentration | Days on additive | Days 18 to 31 |
| CON | none | basal diet | basal diet |
| I | 0.2 percent | 14 | basal diet |
| II | 0.3 percent | 14 | basal diet |
| III | 0.4 percent | 14 | basal diet |
| IV | 0.2 percent | 28 | additive |
| V | 0.3 percent | 28 | additive |
| VI | 0.4 percent | 28 | additive |
A one-rate trial cannot separate how much from how long, and those are the two numbers anyone buying feed needs. So the design here is a dose-response, and the piglet feed additive trial design treats herbal feed additive dose and duration as two factors instead of one.
The additive is a fermented Chinese herbal preparation, a finished product containing 18 herbs plus probiotics and mixed into the diet by weight. It carries live cultures as well as plant material, which makes probiotic and herbal feed additive a better description than either half on its own.
| Element | Detail |
| Base | Compound Chinese herbal additive (CCHA): fermented preparations of 18 medicinal herbs plus probiotics |
| Named herbs | Coptidis Rhizoma, Scutellariae Radix, Lonicerae Japonicae Flos, Ephedrae Herba, Armeniacae Semen Amarum, Atractylodis Macrocephalae Rhizoma, Codonopsis Radix, Forsythiae Fructus, Poria |
| Traditional actions combined | Clearing heat and resolving toxin, cooling the blood and dispersing stasis, tonifying the spleen and kidney, promoting diuresis |
| Rationale for blending | The herbs are used in combination because the combination is expected to outperform any single herb |
| Form | Fermented commercial finished product, dosed into the diet by weight |
The basal diet is a typical nursery formula carrying a lot of animal protein. That matters later, because crude protein digestibility turned out to be the endpoint with the sharpest dose sensitivity.
| Ingredient | Percent of diet |
| Corn | 63.20 |
| Soybean meal (CP 37 percent) | 19.00 |
| Fish meal | 8.60 |
| Whey powder | 4.80 |
| Glucose | 1.00 |
| Premix | 1.00 |
| Limestone | 0.70 |
| Calcium hydrogen phosphate | 0.60 |
| Acidifier (citric acid) | 0.30 |
| Sodium chloride | 0.30 |
| L-Lysine HCl | 0.30 |
| DL-Methionine | 0.10 |
| L-Threonine | 0.10 |
| Total | 100.00 |
Calculated nutrient levels for the same diet, on an air-dry basis: digestible energy 3.25 Mcal/kg, crude protein 18.60 percent, standardised ileal digestible lysine 1.12 percent, SID methionine plus cysteine 0.69 percent, SID threonine 0.79 percent, SID tryptophan 0.19 percent, calcium 0.82 percent, total phosphorus 0.65 percent.
The whole trial on one screen
Seventeen indicators moved in a useful direction somewhere in the study. No single dose won all of them. Percent changes below are calculated from the group means reported for each indicator.
| Indicator | Best treatment group | Best value | Untreated control | Change |
| Final body mass | IV (0.2 percent, 28 days) | 18.96 kg | 16.60 kg | +2.36 kg |
| Average daily gain | IV | 401.60 g/day | 309.48 g/day | +29.8 percent |
| Average daily feed intake | IV | 604.22 g/day | 489.16 g/day | +23.5 percent |
| Feed to gain ratio | IV | 1.51 | 1.59 | -5.0 percent |
| Crude protein digestibility | V (0.3 percent, 28 days) | 83.64 percent | 75.53 percent | +8.11 points |
| Dry matter digestibility | VI (0.4 percent, 28 days) | 81.64 percent | 76.56 percent | +5.08 points |
| Serum total protein | V | 68.29 g/L | 53.42 g/L | +27.8 percent |
| Serum albumin | III (0.4 percent, 14 days) | 17.95 g/L | 12.94 g/L | +38.7 percent |
| Alanine transaminase | IV | 80.82 U/L | 96.23 U/L | -16.0 percent |
| Aspartate transaminase | IV | 57.97 U/L | 66.10 U/L | -12.3 percent |
| Immunoglobulin G | V | 142.73 micrograms/mL | 107.82 micrograms/mL | +32.4 percent |
| Interleukin-2 | VI | 67.54 ng/L | 56.70 ng/L | +19.1 percent |
| Tumour necrosis factor alpha | VI | 161.38 ng/L | 175.60 ng/L | -8.1 percent |
| Glutathione peroxidase | IV | 354.79 | 286.71 | +23.7 percent |
| Total antioxidant capacity | V | 0.20 mM | 0.10 mM | +100 percent |
| Superoxide dismutase | IV | 45.05 U/mL | 32.95 U/mL | +36.7 percent |
| Malondialdehyde | IV | 5.27 nmol/L | 8.57 nmol/L | -38.5 percent |
Run your eye down the second column instead of the numbers. Group IV owns growth, liver enzymes and most of the antioxidant panel. Group V owns protein digestibility, serum protein and immunoglobulins. Group VI, which is the most additive for the longest time, wins two cytokine measurements and loses on everything a farm actually gets paid for. That column is the study in miniature.
Growth: the dose curve turns over
| Group | Concentration | Days | Final body mass (kg) | ADG (g/day) | ADFI (g/day) | Feed to gain |
| CON | none | 0 | 16.60 | 309.48 | 489.16 | 1.59 |
| I | 0.2 percent | 14 | 18.00 | 362.17 | 584.23 | 1.62 |
| II | 0.3 percent | 14 | 18.23 | 376.72 | 595.62 | 1.58 |
| III | 0.4 percent | 14 | 17.44 | 343.54 | 556.95 | 1.62 |
| IV | 0.2 percent | 28 | 18.96 | 401.60 | 604.22 | 1.51 |
| V | 0.3 percent | 28 | 18.17 | 368.30 | 568.51 | 1.55 |
| VI | 0.4 percent | 28 | 15.40 | 270.73 | 448.85 | 1.65 |
Weaned piglet growth performance is easiest to read from the concentration main effect, which strips out duration and leaves the dose curve on its own.
| Main effect | ADG (g/day) | ADFI (g/day) |
| 0 percent | 309.48 | 489.16 |
| 0.2 percent | 381.88 | 594.23 |
| 0.3 percent | 372.51 | 582.06 |
| 0.4 percent | 307.13 | 502.89 |
| 14 days | 360.81 | 578.90 |
| 28 days | 346.88 | 540.52 |
Gain and intake climb from zero to 0.2 percent, sag slightly at 0.3 percent, and collapse back to control level at 0.4 percent. The 0.4 percent average of 307.13 g/day is a statistical match for the untreated control’s 309.48 g/day. Both the linear and the quadratic contrast came out significant at p < 0.01, which is the maths saying “this is a curve, not a slope”. Doubling past the optimum does not buy extra growth. It hands the growth back.
Duration is trickier, and the trick is worth understanding. Averaged over all three rates, 14 days produced a higher daily gain than 28 days, 360.81 g against 346.88 g. That reads like a vote for short feeding. It is not. Group VI sits inside the 28-day average at 270.73 g/day, and it drags the whole mean down with it. Pull that group out and the two 28-day groups hold the best gains in the study.
This is what a significant concentration-by-duration interaction looks like in practice. Duration does not have a direction of its own. It has a direction given a particular rate. Read the two factors together or you will get the answer wrong.
Group IV is the only group that pairs the lowest rate with the longest exposure. It takes the highest gain, the highest intake, the best feed conversion at 1.51 and the heaviest finish at 18.96 kg.
The ugly result: 0.4 percent for 28 days lost to doing nothing
Group VI got the most additive for the longest time and finished at 15.40 kg. The untreated control finished at 16.60 kg. The pigs that got nothing gained 1.2 kg more.
Look at gain and the gap widens. 270.73 g/day against 309.48 g/day is a deficit of 12.5 percent relative to no intervention at all. Intake fell to 448.85 g/day, the lowest in the study and 8.2 percent under the control. Feed to gain drifted out to 1.65. This is not a plateau. A plateau would look like a flat line. This is the response turning around and going the other way.
Digestibility gives you the probable reason. At 0.4 percent, crude protein digestibility was the highest of the three rates after 14 days, at 79.33 percent, and the lowest of the three after 28 days, at 79.67 percent against 83.64 percent for the 0.3 percent group. Protein digestion responds early and then punishes you for insisting.
The commercial reading is uncomfortable but simple. There is an upper limit on how much of this preparation a piglet will tolerate, and 0.4 percent for a full 28 days is past it. Once past it, intake drops first, digestibility follows, and the pen weighs out lighter than a pen that got plain feed. If you have been treating a higher inclusion rate as a safety margin, that assumption is costing you money.
Digestibility: two nutrients, two clocks
| Group | Dry matter | Crude protein | Ether extract | Crude ash |
| CON | 76.56 | 75.53 | 77.59 | 33.27 |
| I | 76.57 | 78.67 | 77.38 | 33.05 |
| II | 76.52 | 78.65 | 76.97 | 33.13 |
| III | 76.62 | 79.33 | 76.45 | 33.58 |
| IV | 80.37 | 82.50 | 77.68 | 33.79 |
| V | 81.39 | 83.64 | 78.03 | 34.09 |
| VI | 81.64 | 79.67 | 77.13 | 34.42 |
| Main effect, 14 days | 76.57 | 78.89 | 76.93 | 33.25 |
| Main effect, 28 days | 81.13 | 81.94 | 77.61 | 34.10 |
All values are percentages. Apparent nutrient digestibility in piglets came from total collection over the last three days of the trial, so these are whole-tract figures.
Every treatment group beat the control on crude protein digestibility in piglets at p < 0.05. Dry matter digestibility ignored the rate completely (p = 0.57) and followed the calendar (p < 0.01). Two nutrients, two different drivers, in the same gut.
Take dry matter first. Groups I, II and III landed between 76.52 and 76.62 percent. The control was 76.56 percent. Three different rates, no difference from plain feed. Groups IV, V and VI landed between 80.37 and 81.64 percent. Same three rates, roughly four points better. The only thing separating those two sets of groups is whether the additive was still going into the feed during the second half of the trial. So the dry matter gain is not the additive working harder. It is the additive being present while the gut finished maturing.
Crude protein runs faster and then hits a wall. After 14 days the 0.4 percent group had the best protein digestibility of the three at 79.33 percent. After 28 days the order had flipped and that same rate had the worst. The significant interaction for crude protein (p < 0.01) is the formal version of that sentence.
Ether extract barely moved. The full range across all seven groups was 76.45 to 78.03 percent, with no significant effect from rate or duration (p = 0.30 and p = 0.13). If you were hoping to justify a fat utilization claim from this data set, there is nothing here to build it on. Crude ash improved with longer feeding, 33.25 percent at 14 days against 34.10 percent at 28 days (p = 0.03).
Blood chemistry: more protein in circulation, quieter liver enzymes
| Group | Total protein (g/L) | Albumin (g/L) | Blood urea nitrogen (mmol/L) | AST (U/L) | ALT (U/L) |
| CON | 53.42 | 12.94 | 2.47 | 66.10 | 96.23 |
| I | 57.75 | 16.48 | 2.83 | 64.20 | 92.31 |
| II | 62.86 | 14.55 | 4.04 | 63.23 | 92.94 |
| III | 65.85 | 17.95 | 3.41 | 63.10 | 91.02 |
| IV | 63.95 | 16.27 | 3.06 | 57.97 | 80.82 |
| V | 68.29 | 15.61 | 3.17 | 60.65 | 83.72 |
| VI | 59.69 | 16.37 | 2.85 | 61.01 | 90.68 |
Total protein and albumin are read as proxies for how well the animal is absorbing and using dietary protein. Every treatment group sat above the control on both. Serum total protein in piglets peaked at 68.29 g/L in group V against 53.42 g/L, up 27.8 percent. Albumin peaked at 17.95 g/L in group III against 12.94 g/L, up 38.7 percent. Blood urea nitrogen came out higher in all six treatment groups than in the control, which fits: more absorbed protein means more deamination, and the nitrogen has to go somewhere.
The liver enzymes are the better half of the table. Aspartate transaminase and alanine transaminase both fell significantly in treated groups at p < 0.05, and both fell furthest in group IV, to 57.97 U/L and 80.82 U/L against 66.10 U/L and 96.23 U/L. Alanine transaminase is the more sensitive of the two and its fall of 16.0 percent is the largest percentage move anywhere in the blood panel. Alkaline phosphatase and acid phosphatase did not budge in any comparison, so this is a transaminase effect, not a general liver shift.
Time amplified it. Averaged across the six treatment groups, alanine transaminase measured 93.13 U/L after 14 days and 87.86 U/L after 28 days, with the sharpest drop at the lowest rate. Falling transaminase in a growing piglet is the direction you want, and it needs weeks to appear. Creatine kinase, the muscle damage marker, was lower in every treated group than in the control, from 6.17 U/L down into a range of 5.08 to 5.46 U/L.
Immunity: this one is about time, not about rate
| Group | IgA (microg/mL) | IgM (microg/mL) | IgG (microg/mL) | IL-2 (ng/L) | IL-4 (ng/mL) | TNF-alpha (ng/L) |
| CON | 27.78 | 7.97 | 107.82 | 56.70 | 42.36 | 175.60 |
| I | 27.94 | 8.24 | 118.42 | 58.68 | 43.06 | 173.10 |
| II | 28.28 | 8.30 | 109.34 | 57.97 | 42.03 | 172.60 |
| III | 27.83 | 8.38 | 120.28 | 60.33 | 44.28 | 172.51 |
| IV | 28.38 | 9.03 | 138.64 | 61.77 | 48.50 | 166.03 |
| V | 28.45 | 8.94 | 142.73 | 64.36 | 51.73 | 164.25 |
| VI | 28.07 | 8.66 | 135.99 | 67.54 | 49.29 | 161.38 |
| Main effect, 14 days | 28.02 | 8.31 | 116.11 | 58.99 | 43.12 | 172.74 |
| Main effect, 28 days | 28.30 | 8.87 | 139.12 | 64.55 | 49.84 | 163.88 |
Concentration stopped mattering here. Serum immune markers in piglets answered to the calendar instead. The rate main effect was not significant for a single immunoglobulin or cytokine, with one exception. Interleukin-2 climbed in a straight line as inclusion went up, and that linear trend was significant at p < 0.05.
Duration carried almost everything. Between the 14-day and 28-day averages, immunoglobulin M went from 8.31 to 8.87 micrograms per millilitre, immunoglobulin G from 116.11 to 139.12, interleukin-2 from 58.99 to 64.55 ng/L and interleukin-4 from 43.12 to 49.84 ng/mL, all at p < 0.01. Tumour necrosis factor alpha went the other way, down from 172.74 to 163.88 ng/L, also at p < 0.01. Immunoglobulin A did nothing at all, sitting between 27.78 and 28.45 micrograms per millilitre across all seven groups.
So a two-week immune assessment will understate this product, badly. If you screen an immunomodulatory feed additive over 14 days and see nothing, look at your trial length before you blame the additive. Immunoglobulin G in piglets shows the point cleanly. It carried a significant concentration-by-duration interaction at p < 0.01, meaning it needed a usable rate and enough weeks together. Neither one alone was enough.
Two numbers are worth pulling out. Group V ended with immunoglobulin G at 142.73 micrograms per millilitre, 32.4 percent above the control, and interleukin-4 at 51.73 ng/mL, 22.1 percent above. The highest-rate group produced the biggest rise in interleukin-2, 67.54 ng/L against 56.70 ng/L, and the biggest fall in tumour necrosis factor alpha, 161.38 ng/L against 175.60 ng/L. Those last two numbers look good standing alone. They arrived in the group with the worst growth in the study. An attractive immune reading and a good production outcome are two separate claims, and the trade between them is real.
Antioxidants: where the biggest percentage moves showed up
| Group | GSH-Px | T-AOC (mM) | SOD (U/mL) | MDA (nmol/L) |
| CON | 286.71 | 0.10 | 32.95 | 8.57 |
| I | 316.07 | 0.11 | 33.41 | 5.90 |
| II | 306.20 | 0.09 | 34.50 | 7.14 |
| III | 297.74 | 0.10 | 35.03 | 7.50 |
| IV | 354.79 | 0.18 | 45.05 | 5.27 |
| V | 336.81 | 0.20 | 43.40 | 5.31 |
| VI | 323.46 | 0.17 | 44.25 | 5.73 |
| Main effect, 14 days | 306.67 | 0.10 | 34.49 | 6.85 |
| Main effect, 28 days | 338.35 | 0.19 | 44.23 | 5.44 |
Glutathione peroxidase is reported without a unit in the source data, so only relative comparisons can be made here.
Four markers, four different behaviors. This is the most informative table in the study.
Glutathione peroxidase activity rose in every treated group and was significantly affected by rate at p < 0.01, in the wrong direction. Higher inclusion produced lower activity. The 0.2 percent average was 335.43 against 286.71 in the control, and the 0.4 percent average fell back to 310.60. Group IV alone reached 354.79, which is 23.7 percent above the control.
Total antioxidant capacity in piglets delivered the biggest proportional change in the entire data set. The control sat at 0.10 mM. Group V reached 0.20 mM. It doubled. It also carried the only significant concentration-by-duration interaction in the antioxidant panel at p < 0.05, and the shape of that interaction is the interesting part: under short feeding the peak was at 0.2 percent, and under long feeding the peak moved to 0.3 percent. Change the clock and the optimum changes with it.
Superoxide dismutase ignored the rate and read the calendar. Rate had no significant effect at all (p = 0.42). Duration was highly significant, with activity running 34.49 U/mL at 14 days and 44.23 U/mL at 28 days, up 28.2 percent. That is the cleanest evidence in the study that part of what is happening here is accumulation rather than dose.
Malondialdehyde in piglets is a damage marker rather than a defense, and it fell in every treated group. Rate affected it significantly at p = 0.02, again with the trend running the wrong way as dose increased. Group IV posted the lowest value at 5.27 nmol/L against 8.57 nmol/L, down 38.5 percent.
Line the four up and the recommendation writes itself. The 0.2 percent, 28-day combination in group IV leads on glutathione peroxidase, superoxide dismutase and malondialdehyde at the same time. Three of four.
Gut microbiota: adjusted, not rebuilt
The gut microbiota of weaned piglets was profiled by 16S rRNA sequencing. Sequencing returned 558,262 raw reads. 494,680 survived quality control, a retention rate of 88.61 percent. Reads ran from 176 to 433 base pairs with a mean of 409. In total 20,601 operational taxonomic units came out of the data, averaging 2,943 per sample. Only 8 units were shared by all seven groups, which is 0.04 percent of the total. Almost everything in this community is animal-specific.
| Group | Firmicutes (percent) | Bacteroidetes (percent) | Actinobacteria (percent) | Firmicutes change vs control | Notable genus-level results |
| CON | 88.01 | 8.19 | 0.09 | baseline | Lactobacillus 10.93 percent, Prevotella 2.60 percent |
| I | 90.88 | 7.98 | 0.05 | +2.87 | Lactobacillus 4.48 percent, Clostridium 6.16 percent |
| II | 86.55 | 11.56 | 0.61 | -1.46 | Clostridium 6.09 percent, SMB53 5.16 percent |
| III | 93.40 | 5.42 | 0.41 | +5.39 | Clostridium 5.25 percent, Prevotella 4.88 percent |
| IV | 91.11 | 7.64 | 0.24 | +3.10 | Clostridium 10.11 percent, SMB53 5.90 percent |
| V | 87.53 | 9.18 | 1.36 | -0.48 | Clostridium 7.09 percent, Prevotella 2.27 percent |
| VI | 76.30 | 6.11 | 15.69 | -11.71 | Lactobacillus 37.99 percent, Olsenella 14.94 percent |
Start with the count of unique units, because it runs against instinct. The control group came out with the most, 3,687 units or 17.8 percent of the total. Group IV, the best group on every production measure, came out with the fewest, 1,084 units or 5.3 percent. The more effective treatment produced a narrower community, not a wider one. More diversity is not automatically better, and this data set will not support that assumption.
At the phylum level the direction of change depends on the group. Firmicutes rose against the control in groups I, III and IV by 2.87, 5.39 and 3.10 percentage points and fell in groups II, V and VI by 1.46, 0.48 and 11.71 points. You cannot call this additive Firmicutes-promoting without adding a lot of conditions. Actinobacteria make the same point harder: the control sat at 0.09 percent and group VI reached 15.69 percent, an increase of more than 170 times, all of it inside one group.
The Firmicutes to Bacteroidetes ratio, worked out from those two shares, ran from about 7.5 in group II up to about 17.2 in group III. The control sat at about 10.7. Track it if you like. Do not turn it into a health score.
Now the part that matters most. Nothing happened at the community level. Beta diversity analysis by principal coordinates and Bray-Curtis non-metric multidimensional scaling found no statistically significant separation between treatment groups and the control. PERMANOVA returned p > 0.05. The ordination itself fit properly, with a stress value of 0.000542, so this is not a weak model failing to find a difference that was there.
The honest summary is that the blend adjusts particular genera and leaves the community architecture roughly where it was. That is a narrower claim than the word “microbiome” usually carries, and it is the claim the data supports.
What to do with this: seven decisions
- Dose low and dose long. The best set of outcomes came from the lowest rate held for the longest period. If one combination has to be chosen before any farm data exists, it is 0.2 percent for the full 28 days.
- Do not treat a higher rate as a safety margin. At 28 days, 0.4 percent finished lighter than doing nothing, with intake 8.2 percent lower and the feed to gain ratio in piglets out at 1.65. More is a risk here, not a buffer.
- Judge immune and antioxidant endpoints at 28 days, not 14. Immunoglobulin G, immunoglobulin M, interleukin-2, interleukin-4, superoxide dismutase and total antioxidant capacity all answered to duration rather than to rate. A two-week trial reports a false negative on every one of them.
- Expect the optimum rate to move with the duration. Total antioxidant capacity peaked at 0.2 percent under short feeding and 0.3 percent under long feeding. The optimum is a pair of numbers.
- Watch feed intake first. In the group that went wrong, intake fell 8.2 percent before anything else moved. If intake drops after a change involving this class of additive, check the inclusion rate before you start looking for an infectious cause.
- Do not score performance with Lactobacillus abundance in piglets. The worst group in the trial had the highest Lactobacillus share at 37.99 percent, more than triple the control. Genus abundance describes the community. It does not describe how well the pig is doing.
- Keep the additive in its proper place. A feed additive that improves gain, immune status and antioxidant capacity reduces the pressure that leads to treatment. It does not treat a sick pig. Therapeutic antimicrobials stay necessary for clinical disease, and withdrawal periods and veterinary oversight are unaffected by anything here.
Limitations: what this trial cannot tell you
The control design is clean but the constraints are real, and they should shape how much weight any single number above carries.
- No antibiotic comparator. The control group got no additive and no antibiotics, so the comparison is against no intervention rather than against an in-feed antimicrobial. The common claim that a herbal blend can replace antibiotics in the nursery is not tested here and cannot be concluded from this work.
- No baseline blood samples. Blood was drawn only at the end. Within-animal change over time is unknown, and random allocation reduces the risk of baseline differences without eliminating it.
- Three pens per group. Growth and digestibility used the pen as the experimental unit, which leaves three replicates per group for those traits. The effects are large, but the replication is thin.
- No economic analysis. The trial did not weigh the cost of the additive against the value of the extra gain. The optima reported here are biological. A farm’s break-even rate will be a different number, and it will move with the price of the preparation and the price of weaned pigs.
- The mechanism was not measured. The phytochemical composition of the blend was not re-analyzed during the trial and no pathway work was done. The accumulation and selective regulation explanations above fit the data. They are not proven by it.
- One formulation, one farm, one batch. Eighteen herbs plus probiotics in a fixed blend means no single herb can be credited or blamed. A different blend, a different fermentation batch or a different piglet age could behave differently.
- Ether extract digestibility never moved significantly. Anyone hunting for a fat utilization claim will not find one here, and should not infer one from the protein and dry matter results.
Bottom line
The useful answer for Chinese herbal feed additives for piglets is narrower than “they work.” They work at a low rate held for a long time, and they stop working, then reverse, when the rate is pushed. The 0.2 percent, 28-day combination produced 401.60 g of daily gain against 309.48 g in the untreated control, a 5.0 percent better feed conversion, higher serum protein, a 16.0 percent reduction in alanine transaminase, a 32.4 percent rise in immunoglobulin G at the protein-optimizing rate and a 38.5 percent reduction in malondialdehyde. The 0.4 percent, 28-day combination produced a pen that finished lighter than the control pen.
Set the rate from a dose-response trial rather than from the label. Set the duration from the endpoint you actually sell. Treat every point of inclusion above the optimum as a cost with no upside attached.
FAQ
What are Chinese herbal feed additives for piglets?
Chinese herbal feed additives for piglets are fermented preparations of medicinal herbs, usually with probiotics, dosed into the diet at a low percentage. Their active fractions include polysaccharides, flavonoids, saponins, essential oils and alkaloids. The effect is not a single drug action but a combined push on feed intake, digestion, immune status and oxidative stress. One trial used a blend of 18 herbs.
Do Chinese herbal feed additives improve piglet growth?
They can, when the dose and the duration are both right. In this trial average daily gain rose from 309.48 g/day in the untreated control to 401.60 g/day in the group fed 0.2 percent for 28 days, an increase of 29.8 percent. Average daily feed intake rose 23.5 percent and feed to gain improved from 1.59 to 1.51. The same blend at 0.4 percent for 28 days reduced gain below the control.
What is the best dose and feeding duration?
In this trial, 0.2 percent fed for the full 28 days produced the best overall result: the highest gain, the highest feed intake, the best feed conversion, the heaviest finishing weight and the lowest liver enzyme activity. Concentration and duration interacted significantly for gain, intake, crude protein digestibility and immunoglobulin G, which means neither factor can be optimized on its own.
What happens if you feed 0.4 percent for 28 days?
Performance falls below the untreated control. That group finished at 15.40 kg against 16.60 kg for the control, with average daily gain down 12.5 percent, feed intake down 8.2 percent and feed to gain worsened to 1.65. It also had the lowest crude protein digestibility of the three concentrations at 28 days. This is an inverted dose response, not a plateau.
How long do you have to feed the additive before immune markers respond?
Roughly four weeks. Concentration had no significant effect on any immunoglobulin or cytokine except interleukin-2, while duration was significant for immunoglobulin M, immunoglobulin G, interleukin-2, interleukin-4 and tumour necrosis factor alpha. Across all concentrations, immunoglobulin G rose from 116.11 to 139.12 micrograms per millilitre and interleukin-4 from 43.12 to 49.84 ng/mL between 14 and 28 days.
Which serum indicators moved the most?
Albumin rose the most in percentage terms, from 12.94 to 17.95 g/L at the peak, a gain of 38.7 percent. Total protein peaked at 68.29 g/L against 53.42 g/L, a rise of 27.8 percent. On the enzyme side, alanine transaminase fell from 96.23 to 80.82 U/L, a reduction of 16.0 percent, and aspartate transaminase fell from 66.10 to 57.97 U/L. Alkaline and acid phosphatase did not move.
How much did antioxidant capacity improve?
Total antioxidant capacity doubled, from 0.10 mM in the control to 0.20 mM at the peak. Glutathione peroxidase rose from 286.71 to 354.79, up 23.7 percent, and superoxide dismutase from 32.95 to 45.05 U/mL, up 36.7 percent. Malondialdehyde, the damage marker, fell from 8.57 to 5.27 nmol/L, a reduction of 38.5 percent. Superoxide dismutase responded to duration rather than to dose.
Did the herbal additive change the piglet gut microbiota?
Only selectively. Firmicutes, Bacteroidetes and Actinobacteria shares shifted in some groups, and Lactobacillus reached 37.99 percent in one group. But beta diversity analysis found no statistically significant separation between treatment groups and the control, with PERMANOVA returning p > 0.05. The reliable reading is that the blend adjusts specific genera while leaving the overall community structure largely intact.
Is a high Lactobacillus count a good performance marker?
No, and this trial is the reason to be careful. The group with the highest Lactobacillus abundance, at 37.99 percent of the genus-level community, was also the worst performer on every growth measure, finishing at 15.40 kg against 16.60 kg for the control. Genus-level abundance is a description of the community, not a proxy for how well the pig is doing.
Can these additives replace antibiotics in piglets?
This trial does not answer that question. The control group received no additive and no antibiotics, so the comparison is against no intervention rather than against an in-feed antimicrobial. The results show that a herbal blend can move growth, immune and antioxidant endpoints in the right direction. Whether it matches an antimicrobial requires a direct head-to-head trial, which this study did not run.
What are the main limitations of this evidence?
Three stand out. There was no antibiotic comparator, so no replacement claim can be made. There were no baseline blood samples, so within-animal change over time is unknown. And growth and digestibility used the pen as the experimental unit with only three replicates per group. There was also no cost analysis, so the biological optimum reported here is not automatically the financial one.
How should a producer trial this on their own farm?
Run a dose-response first, not a single-rate trial, and run each rate for the full period you intend to use. Include an untreated control pen and, where legal and appropriate, your existing program as a comparator. Score feed intake weekly, because it moved first in the group that went wrong. Judge immune and antioxidant benefits only after four weeks. Do not assume a higher rate is safer.
