Varying starch to fat ratios in pelleted diets: II. Effects on intestinal histomorphometry, Clostridium perfringens and short-chain fatty acids in Eimeria-challenged broiler chickens

Figures & data

Table 1. Primers and probes used for qPCR analysis

Target	Description	Nucleic acid sequences 5ʹ to 3ʹ with probe dyes (Tm)	Product length (bp)	Reference
cpa	Forward primer	AAG AAC TAG TAG CTT ACA TAT CAA CTA GTG GTG (57.3°C)	124	(Albini et al. 2008)
	Reverse primer	TTT CCT GGG TTG TCC ATT TCC (55.4°C)
	Probe	HEX-TTG GAA TCA -ZEN- AAA CAA AGG ATG GAA AAA CTC AAG-IBFQ (58.4°C)
netB	Forward primer	GGC GGT AAT ATA TCT GTT GAA GG (53.1°C)	168	(Schlegel et al. 2012)
	Reverse primer	ACC GTC CTT AGT CTC AAC (51.0°C)
	Probe	FAM-ACT GCT GGT -ZEN- GCT GGA ATA AAT GCT TCA-IBFQ (60.8°C)

Table 2. Effect of dietary starch to fat ratios on intestinal histomorphometry on days 16, 21–23 and 29.^1.

		Diet^2
Age	Variable	HS	LS	P-value^3
16 days	Villus length (µm)	1255 ± 33	1187 ± 30	0.154
	Crypt depth (µm)	175 ± 5	179 ± 4	0.493
	Villus:crypt ratio	7.23 ± 0.2	6.67 ± 0.3	0.153
21–23 days	Villus length (µm)	1570 ± 78	1650 ± 83	0.497
	Crypt depth (µm)	175 ± 7	192 ± 7	0.111
	Villus:crypt ratio	9.09 ± 0.6	8.74 ± 0.6	0.669
29 days	Villus length (µm)	1689 ± 48	1440 ± 33	<0.001
	Crypt depth (µm)	174 ± 5	176 ± 8	0.875
	Villus:crypt ratio	9.83 ± 0.5	8.32 ± 0.4	0.037

¹Values are means ± SEM.

²HS: high starch to fat ratio diet; LS: low starch to fat ratio diet.

³Independent two-sample t-test.

Figure 1. Effect of dietary starch to fat ratios on caecal Clostridium perfringens counts (log₁₀ cfu/g) during days 21–23. Boxplots with medians indicated by horizontal lines and means indicated by diamonds. Based on samples from 36 chickens per diet. HS: high starch to fat ratio diet; LS: low starch to fat ratio diet. cfu/g = colony forming units per gram

Table 3. The percentage of netB-positive and netB-negative caecal samples.^1.

Age	Diet	netB-negative		netB-positive
16 days	HS	25%	21%	75%	79%
	LS	17%		83%
21–23 days	HS	8%	8%	92%	92%
	LS	8%		92%
29 days	HS	0%	0%	100%	100%
	LS	0%		100%
Total			10%		90%

¹Based on samples from 12 chickens per diet per time point.

HS: high starch to fat ratio diet; LS: low starch to fat ratio diet.

Figure 2. Effect of dietary starch to fat ratios on the Clostridium perfringens netB:cpa ratio in caecal samples on days 16, 21–23 and 29

Boxplots with medians indicated by horizontal lines and means indicated by diamonds. Based on samples from 12 chickens per diet per time point. Statistical analysis carried out by Mann-Whitney U test. HS: high starch:fat ratio diet; LS: low starch:fat ratio diet; ns = not significant.

Table 4. Effect of dietary starch to fat ratios on short chain fatty acids (SCFAs; µmol/g) in caecum.^1.

	Day 16			Day 21–23			Day 29
	HS	LS	P-value	HS	LS	P-value	HS	LS	P-value
Acetic acid	58.24 ± 4.17	43.43 ± 2.95	0.016	66.75 ± 2.76	67.28 ± 4.99	0.729	62.34 ± 3.80	55.79 ± 4.37	0.184
Propionic acid	3.29 ± 0.33	1.85 ± 0.35	0.006	4.32 ± 0.49	4.39 ± 0.70	0.624	4.33 ± 0.24	4.09 ± 0.47	0.356
Butyric acid	10.21 ± 0.85	9.57 ± 0.95	0.580	12.96 ± 1.27	13.72 ± 0.86	0.419	11.24 ± 1.37	11.67 ± 1.31	0.773
Total SCFAs	73.94 ± 4.99	55.96 ± 3.78	0.016	86.89 ± 4.01	88.23 ± 5.65	0.356	80.64 ± 5.19	73.59 ± 5.82	0.299

¹Values are means (µmol/g) ± SEM. Statistical analysis carried out by Mann-Whitney U test.

HS: high starch to fat ratio diet; LS: low starch to fat ratio diet.

Albini, S., I. Brodard, A. Jaussi, N. Wollschlaeger, J. Frey, R. Miserez, and C. Abril. 2008. “Real-time Multiplex PCR Assays for Reliable Detection of Clostridium Perfringens Toxin Genes in Animal Isolates.” Veterinary Microbiology 127 (1–2): 179–185. doi:10.1016/j.vetmic.2007.07.024.

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Schlegel, B. J., V. J. NOWELL, V. R. PARREIRA, G. SOLTES, and J. F. PRESCOTT. 2012. “Toxin-associated and Other Genes in Clostridium Perfringens Type A Isolates from Bovine Clostridial Abomasitis (BCA) and Jejunal Hemorrhage Syndrome (JHS).” Canadian Journal of Veterinary Research 76 (4): 248–254.

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