Table 2 Assessment of reporting quality of included studies

1

Provide as accurate and concise a description of the content of the article as possible.

4241

2196

97.1

2045

98.3

2

Provide an accurate summary of the background, research objectives (including details of the species or strain of animal used), key methods, principal findings, and conclusions of the study

4117

2084

92.2

2033

97.7

 Background

3a

Include sufficient scientific background (including relevant references to previous work) to understand the motivation and context for the study, and explain the experimental approach and rationale.

4071

2057

91.0

2014

96.8

3b

Explain how and why the animal species and model being used can address the scientific objectives and, where appropriate, the study’s relevance to human biology.

1609

737

32.6

872

41.9

 Objectives

4

Clearly describe the primary and any secondary objectives of the study, or specific hypotheses being tested.

4248

2198

97.2

2050

98.5

 Ethical statement

5

Indicate the nature of the ethical review permissions, relevant licenses (e.g. Animal [Scientific Procedures] Act 1986), and national or institutional guidelines for the care and use of animals, that cover the research.

286

125

5.53

161

7.74

 Study design

6a

For each experiment, give brief details of the study design, including: the number of experimental and control groups.

3741

1893

83.7

1848

88.8

6b

For each experiment, give brief details of the study design, including: any steps taken to minimise the effects of subjective bias when allocating animals to treatment (e.g., randomisation procedure) and when assessing results (e.g., if done, describe who was blinded and when).

3961

2034

90.0

1927

92.6

6c

For each experiment, give brief details of the study design, including: the experimental unit (e.g. a single animal, group, or cage of animals).

4312

2245

99.3

2067

99.3

6d

For each experiment, give brief details of the study design, including: A time-line diagram or flow chart can be useful to illustrate how complex study designs were carried out.

63

15

0.66

48

2.31

 Experimental procedures

7a

For each experiment and each experimental group, including controls, provide precise details of all procedures carried out. For example: How (e.g., drug formulation and dose, site and route of administration, anaesthesia and analgesia used [including monitoring], surgical procedure, method of euthanasia). Provide details of any specialist equipment used, including supplier(s).

4172

2165

95.8

2007

96.4

7b

For each experiment and each experimental group, including controls, provide precise details of all procedures carried out. For example: When (e.g., time of day).

269

214

9.46

55

2.64

7c

For each experiment and each experimental group, including controls, provide precise details of all procedures carried out. For example: Where (e.g., home cage, laboratory, water maze).

513

309

13.7

204

9.80

7d

For each experiment and each experimental group, including controls, provide precise details of all procedures carried out. For example: Why (e.g., rationale for choice of specific anaesthetic, route of administration, drug dose used).

1631

806

35.7

825

39.6

 Experimental animals

8a

Provide details of the animals used, including species, strain, sex, developmental stage (e.g., mean or median age plus age range), and weight (e.g., mean or median weight plus weight range).

4162

2160

95.5

2002

96.2

8b

Provide further relevant information such as the source of animals, international strain nomenclature, genetic modification status (e.g. knock-out or transgenic), genotype, health/immune status, drug- or testnaive, previous procedures, etc.

3785

1909

84.4

1876

90.2

 Housing and husbandry

9a

Housing (e.g., type of facility, specific pathogen free (SPF); type of cage or housing; bedding material; number of cage companions; tank shape and material etc. for fish).

1022

409

1819

613

29.5

9b

Husbandry conditions (e.g., breeding programme, light/dark cycle, temperature, quality of water etc. for fish, type of food, access to food and water, environmental enrichment).

928

338

15.0

590

28.4

9c

Welfare-related assessments and interventions that were carried out before, during, or after the experiment.

147

77

3.41

70

3.36

 Sample size

10a

Specify the total number of animals used in each experiment and the number of animals in each experimental group.

3440

1728

76.4

1712

82.3

10b

Explain how the number of animals was decided. Provide details of any sample size calculation used.

1

0

0.00

1

0.05

10c

Indicate the number of independent replications of each experiment, if relevant.

6

4

0.18

2

0.10

 Allocating animals to experimental groups

11a

Give full details of how animals were allocated to experimental groups, including randomization or matching if done.

522

208

9.20

314

15. 1

11b

Describe the order in which the animals in the different experimental groups were treated and assessed.

4070

2100

92.9

1970

94.7

 Experimental outcomes

12

Clearly define the primary and secondary experimental outcomes assessed (e.g., cell death, molecular markers, behavioral changes).

4071

2098

92.8

1973

94.8

 Statistical methods

13a

Provide details of the statistical methods used for each analysis.

3585

1677

74.2

1908

91.7

13b

Specify the unit of analysis for each dataset (e.g. single animal, group of animals, single neuron).

2840

1287

56.9

1553

74.6

13c

Describe any methods used to assess whether the data met the assumptions of the statistical approach.

662

284

12.6

378

18.2

 Baseline data

14

For each experimental group, report relevant characteristics and health status of animals (e.g., weight, microbiological status, and drug- or test-naı¨ve) before treatment or testing (this information can often be tabulated).

223

87

3.85

136

6.54

 Numbers analysed

15a

Report the number of animals in each group included in each analysis. Report absolute numbers (e.g.10/20, not 50%)

3023

1546

68.4

1477

71.0

15b

If any animals or data were not included in the analysis, explain why.

3213

1661

73.5

1552

74.6

 Outcomes and estimation

16

Report the results for each analysis carried out, with a measure of precision (e.g, standard error or confidence interval).

3811

1918

84.8

1893

91.0

 Adverse events

17a

Give details of all important adverse events in each experimental group.

64

21

0.93

43

2.07

17b

Describe any modifications to the experimental protocols made to reduce adverse events.

1

1

0.04

0

0.00

 Interpretation/scientific implications

18a

Interpret the results, taking into account the study objectives and hypotheses, current theory, and other relevant studies in the literature.

4157

2143

94.8

2014

96.8

18b

Comment on the study limitations including any potential sources of bias, any limitations of the animal model, and the imprecision associated with the results.

228

103

4.56

125

6.01

18c

Describe any implications of your experimental methods or findings for the replacement, refinement, or reduction (the 3Rs) of the use of animals in research.

15

4

0.18

11

0.53

 Generalisability/translation

19

Comment on whether, and how, the findings of this study are likely to translate to other species or systems, including any relevance to human biology.

281

134

5.93

147

7.06

 Funding

20

List all funding sources (including grant number) and the role of the funder(s) in the study.

47

15

0.66

32

1.54