. 2021 Sep 29;8:746765. doi: 10.3389/fnut.2021.746765

Table 4.

Regression and subgroup analysis of studies included in the meta-analysis.

Outcome	Subgroup		N^a	$P_{regression}^{b}$	WMD (95% CI)	P	I²	P _{heterogeneity}
IMF (%)	PUFA source	CLA	193	0.020	0.542 (0.343–0.741)	<0.001	86.4%	<0.001
		Linseed	81		0.307 (0.047–0.566)	0.021	86.6%	<0.001
	Concentration	High concentration	97	0.021	0.461 (0.208–0.715)	<0.001	92.2%	<0.001
		Low concentration	177		0.456 (0.276–0.635)	<0.001	72.0%	<0.001
	Initial growth stage	Growing pigs	200	0.006	0.563 (0.395–0.731)	<0.001	75.7%	<0.001
		Finishing pigs	74		0.254 (−0.061 to 0.569)	0.114	93.6%	<0.001
Drip loss (%)	PUFA source	CLA	163	0.828	−0.147 (−0.314 to 0.021)	0.086	0.0%	0.857
		Linseed	105		−0.299 (−0.959 to 0.361)	0.374	81.9%	<0.001
	Concentration	High concentration	147	0.891	−0.268 (−0.775 to 0.240)	0.301	74.9%	<0.001
		Low concentration	121		−0.128 (−0.307 to 0.050)	0.159	0.0%	0.878
	Initial growth stage	Growing pigs	170	0.868	−0.135 (−0.301 to 0.031)	0.111	0.0%	0.777
		Finishing pigs	98		−0.258 (-0.955 to 0.440)	0.469	81.6%	<0.001
L*	PUFA source	CLA	205	0.226	−0.155 (−0.590 to 0.280)	0.485	14.0%	0.287
		Linseed	67		−1.740 (−3.267 to −0.213)	0.026	81.9%	<0.001
	Concentration	High concentration	65	0.932	−1.366 (−2.717 to −0.015)	0.047	78.9%	<0.001
		Low concentration	207		−0.172 (−0.627 to 0.283)	0.459	17.4%	0.254
	Initial growth stage	Growing pigs	182	0.266	−0.091 (−0.652 to 0.470)	0.750	34.5%	0.092
		Finishing pigs	90		−1.331 (−2.354 to −0.308)	0.011	72.5%	<0.001
a*	PUFA source	CLA	205	0.500	0.137 (−0.265 to 0.538)	0.504	73.3%	<0.001
		Linseed	67		−0.066 (−0.578 to 0.446)	0.800	36.8%	0.148
	Concentration	High concentration	65	0.269	0.146 (−0.364 to 0.656)	0.574	54.7%	0.024
		Low concentration	207		0.053 (−0.370 to 0.476)	0.806	73.0%	<0.001
	Initial growth stage	Growing pigs	182	0.179	0.227 (−0.141 to 0.595)	0.226	61.7%	0.001
		Finishing pigs	90		−0.255 (−0.900 to 0.391)	0.439	75.8%	<0.001
b*	PUFA source	CLA	205	0.187	−0.194 (−0.344 to −0.044)	0.011	52.7%	0.005
		Linseed	67		0.184 (−0.140 to 0.508)	0.265	26.7%	0.225
	Concentration	High concentration	65	0.890	0.032 (−0.209 to 0.273)	0.794	17.1%	0.290
		Low concentration	207		−0.180 (−0.351 to −0.009)	0.039	60.3%	0.001
	Initial growth stage	Growing pigs	182	0.686	−0.163 (−0.295 to −0.030)	0.016	32.0%	0.112
		Finishing pigs	90		−0.104 (−0.475 to 0.267)	0.583	70.0%	<0.001
pH 45 min	PUFA source	CLA	108	0.772	0.019 (−0.095 to 0.132)	0.749	64.1%	0.003
		Linseed	105		0.056 (−0.059 to 0.172)	0.337	77.7%	0.002
	Concentration	High concentration	93	0.774	0.058 (−0.064 to 0.179)	0.352	79.9%	<0.001
		Low concentration	120		0.021 (−0.086 to 0.128)	0.704	60.6%	0.003
	Initial growth stage	Growing pigs	118	0.185	−0.003 (−0.078 to 0.072)	0.940	31.6%	0.123
		Finishing pigs	95		0.106 (−0.054 to 0.266)	0.195	87.5%	<0.001
pH 24 h	PUFA source	CLA	195	0.742	−0.006 (−0.023 to 0.11)	0.486	0.0%	0.568
		Linseed	87		−0.034 (−0.049 to −0.018)	<0.001	1.2%	0.420
	Concentration	High concentration	85	0.673	−0.033 (−0.049 to −0.018)	<0.001	0.0%	0.526
		Low concentration	197		−0.006 (−0.023 to 0.011)	0.479	0.0%	0.486
	Initial growth stage	Growing pigs	172	0.108	−0.002 (−0.019 to 0.015)	0.813	0.0%	0.783
		Finishing pigs	110		−0.035 (−0.051 to −0.020)	<0.001	0.7%	0.434

N, total number of pigs.

^bP_regression, P value of regression, significance level P_regression < 0.05. L*, lightness; a*, redness; b*, yellowness.