The Effects of Tannin-Coated and High-Efficiency Zinc Replacing Conventional Zinc Oxide on Growth Performance in Weaned Piglets

This experiment uses weaned piglets as the research subjects, and its objective is:

             ① Investigating the impact of replacing part of conventional zinc oxide in early-weaned piglets' diets with coated tannins on their growth performance.

② Investigate the effects of combining coated tannins with low-dose, highly effective zinc—used together to completely replace high-dose conventional zinc oxide—on the growth performance of late-weaned piglets in their diet.

③ Explore the application differences between two tannin products—Weichangning and Anchangfen M50—with identical effective doses but different coating types;

④ Investigating the effects of coating tannins (Anchangfen M40) combined with highly effective zinc (Haoke Zinc), used as a complete replacement for conventional zinc oxide, on the production performance of weaned piglets.              

Materials and Methods

Experimental Design and Grouping

The trial selected 120 healthy, weaned piglets with an average body weight of 6.40 ± 0.1 kg and similar ages, randomly divided into 5 treatment groups. The experimental period lasted 34 days, divided into two distinct phases: a creep feed phase lasting 17 days, followed by a nursery feed phase also lasting 17 days.

Table 1: Experimental Design for Phase 1 (1–2 Weeks Post-Weaning, Creep Feeding Stage)

Table 2: Experimental Design for Phase 2 (3–4 Weeks After Weaning, Grower Feed Stage)

                                                                       Note: Wei Chang Ning: Enteric-coated plant tannins, with an effective content of ≥50%;                                                                            
                                                                               Anchangfen M50: Slow-release coated plant tannins with an effective content of ≥50%;
                                                                                                                                                                      Anchangfen M40: Slow-release coated plant tannins with an effective content of ≥40%;

      Well-opened zinc: Nano zinc oxide, with an effective ZnO content of ≥70%.                                

Test location and time: The trial was conducted at the Guangdong Academy of Agricultural Sciences' experimental pig farm from August 30, 2023, to October 3, 2023, lasting a total of 34 days.

Experimental Diet

Table 3: Basal Diet for Phase 1 Trial

Table 4: Basal Diet for Phase 2 Trial

  Test indicator measurement: Daily record the feed intake, number and weight of dead or culled pigs, and calculate the average daily gain, daily feed consumption, feed-to-meat ratio, as well as the mortality and diarrhea rates during each phase of the trial.

Results and Analysis

Analysis of the results from the first-phase trial

Table 5: Production Performance of Piglets in Each Group During the First Phase (1–2 Weeks Post-Weaning)

Note: In the same column, identical letter symbols indicate no significant difference (P > 0.05), while different lowercase letters denote a highly significant difference (P < 0.05). The same applies to the table below.

Results indicate that the nutritional programs in Groups 2, 3, and 4 exhibited equivalent efficacy in improving gut health (reducing diarrhea) and enhancing appetite (increasing feed intake) in piglets, with Group 5 performing slightly better. However, when it comes to feed efficiency—as measured by feed-to-meat ratio and piglet weight gain—while the high-dose zinc oxide group successfully prevented diarrhea, its feed-to-meat ratio was higher compared to the nutritional programs that replaced half of the zinc oxide (Groups 2 and 3). Although Group 5 showed lower feed intake and weight gain than Group 2, its feed-to-meat ratio was marginally better than the zinc oxide group, suggesting that the high dose of zinc oxide may impair the gut’s ability to efficiently absorb and convert dietary nutrients.

Analysis of Phase 2 Trial Results

Table 6: Production Performance of Piglets in Each Group During the Second Phase (3–4 Weeks After Weaning)

Results indicate that the nutritional programs in Groups 2, 3, 4, and 5 had equivalent effects on piglet growth performance. However, when evaluating feed efficiency—specifically through feed-to-gain ratios and piglet weight gain—we observed that while the high-dose zinc oxide (Group 2) did enhance feed intake in piglets, Groups 3, 4, and 5, which combined coated tannins with highly bioavailable zinc, demonstrated superior overall production outcomes, including better weight gain and improved feed conversion efficiency.

Analysis of trial results from all phases

Table 7: Production Performance of Piglets in Each Group During the Entire Trial Period (1–4 Weeks After Weaning)

Results indicate that the nutritional programs in Groups 2, 3, and 4 had equivalent effects on piglet growth performance. However, when it comes to feed efficiency—as reflected by feed-to-gain ratio and piglet weight gain—we observed that while the high dose of zinc oxide did encourage increased feed intake in piglets, the combination of coated tannins with highly bioavailable zinc delivered superior production outcomes in terms of both weight gain and feed conversion efficiency.

Conclusion