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The published article used dressed weight (i.e. head, guts, and other body parts removed) as the edible portion (i.e. yield) values for terrestrial species. This was an error, and instead we should have used yield values based on retail cuts of meat, which is consistent with the values used for farmed aquatic species. Therefore, we have replaced the dressed weight values with retail cut values for beef cattle and pigs, including bone-in and boneless values, similar to yield values used for aquatic animals. Chickens are commonly sold in a dressed form (i.e. dressed weight is a retail cut for chickens), so a combination of dressed weight and other retail cut values were used for chickens. We recalculated the protein and calorie efficiencies for these terrestrial species, and the following tables and figure below are corrected for beef cattle, pigs, and chickens: tables 1 and 2 and S4; figure 2. These revisions do not pertain to any data or calculations for aquatic animals.
Table 1. Data used to calculate protein and calorie retention for selected aquatic and terrestrial farmed animal species.
| Species | FCRa | Edible portion of animalb | Feed contentc (g or kcal per 100 g of feed) | Human nutritiond (g or kcal per 100 g serving) | ||
|---|---|---|---|---|---|---|
| Protein | Calories | Protein | Calories | |||
| Carps | 1.5−2.0 | |||||
| Common carp | − | 0.36−0.54 | 17−45 | 175.8−554.2 | 18 | 109−127 |
| Grass carp | − | 0.36−0.54 | 25 | 326.0−345.5 | 17−18 | 112−127 |
| Catfishes | 1.2−2.2 | |||||
| Channel catfish | − | 0.35−0.63 | 28−32 | 345−390 | 15−17 | 117−119 |
| Pangas catfish | − | 0.35−0.63 | 26−32 | 339−388 | 15 | 97 |
| Salmonids | ||||||
| Atlantic salmon | 1.2−1.5 | 0.58−0.88 | 35.5−44 | 372−554.5 | 20 | 208 |
| Rainbow trout | 1.0−2.0 | 0.40−0.82 | 40−47 | 383−454 | 20 | 141 |
| Shrimps | 1.2−2.4 | |||||
| Giant tiger prawn | − | 0.40 | 25−45 | 225−433 | 20 | 85 |
| Whiteleg shrimp | − | 0.62−0.65 | 25−45 | 277−417 | 20 | 85 |
| Tilapias | 1.4−2.4 | 0.37−0.45 | 20−32 | 216−404.4 | 20 | 96 |
| Cattle | 6.0−10 | 0.35−0.51 | 7−15.4 | 188−339 | 15−20 | 214−276 |
| Chicken | 1.7−2.0 | 0.63−0.73 | 18−23 | 320 | 18.6 | 215 |
| Pigs | 2.7−5.0 | 0.37−0.57 | 13.2−20.9 | 326.5−335.1 | 15−18.2 | 211−304 |
aData sources: Tacon and Metian (2008) (aquatic species) [1]; Smil (2013) (livestock species) [2]; Shike (2013) (cattle) [3]; Zuidhof et al (2014) (chicken) [4]; Rabobank Research (2015) (pigs) [5]. bData sources: see table S4. cData sources: see table S5. dData sources: USDA National Nutrient Database for Standard Reference [6]; Shauhua Zahn, Nanyang Technical University (personal communication); Seafood Health Facts [7]; USDA National Nutrient Database terms used for beef: ‘composite of trimmed retail cuts, separable lean and fat, trimmed to 1/8″ fat, all grades, raw’ and ‘variety meats and by-products, mechanically separated beef, raw’; USDA National Nutrient Database term used for chicken: ‘meat and skin, raw’; USDA National Nutrient Database terms used for pork: ‘composite of trimmed leg, loin, shoulder, and spareribs, separable lean and fat, raw’ and ‘fresh, variety meats and by-products, mechanically separated, raw’.
Figure 2. Protein and calorie retention for selected aquatic and terrestrial farmed animal species. Dots represent sample means and bars represent standard deviations. Higher values indicate more efficient retention.
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Standard image High-resolution imageTable 2. Mean FCR and retention values in the current study and past researcha.
| Current study | Cassidy et al (2013) | Shepon et al (2016) | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| FCRb | Feed/edible wt. | Protein retention | Calorie retention | FCR | Feed/edible wt. | Protein retention | Calorie retention | FCR | Feed/edible wt. | Protein retention | Calorie retention | |
| Common carp | 1.7 | 3.78 | 0.15 | 0.09 | ||||||||
| Grass carp | 1.7 | 3.78 | 0.18 | 0.09 | ||||||||
| Channel catfish | 1.4 | 2.87 | 0.18 | 0.11 | ||||||||
| Pangas catfish | 1.4 | 3.02 | 0.17 | 0.09 | ||||||||
| Atlantic salmon | 1.3 | 1.77 | 0.28 | 0.25 | ||||||||
| Rainbow trout | 1.3 | 2.14 | 0.22 | 0.16 | ||||||||
| Giant tiger prawn | 1.7 | 4.25 | 0.14 | 0.06 | ||||||||
| Whiteleg shrimp | 1.7 | 2.68 | 0.22 | 0.09 | ||||||||
| Tilapia | 1.7 | 4.17 | 0.18 | 0.07 | ||||||||
| Aqua. weighted ave. | 1.6 | 3.08 | 0.19 | 0.10 | ||||||||
| Beef cattle | 8.0 | 18.6 | 0.10 | 0.05 | 12.7 | 21.2 | 0.05 | 0.03 | 14 | 36 | 0.03 | 0.03 |
| Pigs | 3.9 | 7.65 | 0.15 | 0.11 | 6.5 | 9.3 | 0.10 | 0.10 | 3.1 | 6.0 | 0.09 | 0.09 |
| Chicken | 1.9 | 2.81 | 0.34 | 0.25 | 2.5 | 3.3 | 0.40 | 0.12 | 1.9 | 4.2 | 0.21 | 0.13 |
| Eggs | 0.35 | 0.22 | 0.31 | 0.17 | ||||||||
| Dairy | 0.43 | 0.40 | 0.14 | 0.17 | ||||||||
aSources: Cassidy et al (2013) [8] and Shepon et al (2016) [9]. bFCRs are average values based on Tacon and Metian (2008) (aquatic species) [1]; Smil (2013) (livestock species) [2]; Shike (2013) (cattle) [3]; Zuidhof et al (2014) (chicken) [4]; and Rabobank Research (2015) (pigs) [5].
Table S4. Edible portion data and sources for terrestrial species.
| Species | Edible portion range | No. of values used | Source |
|---|---|---|---|
| Cattle | 0.35−0.51 | 6 | National Renderers Association [10], Oklahoma Department of Agriculture, Food, and Forestry [11], South Dakota State University Extension [12], University of Kentucky Cooperative Extension Service [13], University of Tennessee Institute for Agriculture [14]. |
| Chicken | 0.63−0.73 | 6 | FAO [15], MSU Extension (adapted from Principles of Meat Science, 4th Ed.) [16], National Renderers Association [10], US Foods, Inc. (expected meat yield from a dressed chicken was multiplied by dressed weight values from FAO and MSU sources to develop two retail cut values) [17]. |
| Pigs | 0.37−0.57 | 8 | Maine Organic Farmers and Gardeners Association [18], National Pork Board [19], National Renderers Association [10], Oklahoma Department of Agriculture, Food, and Forestry [20], University of Kentucky Cooperative Extension Service [13]. |
These changes result in the following text revisions:
- 1.In the abstract, the sentence:Comparing all terrestrial and aquatic animals in the study, chickens are most efficient using these measures, followed by Atlantic salmon.Revision:Comparing all terrestrial and aquatic animals in the study, chickens and Atlantic salmon are most efficient using these measures.
- 2.In the first paragraph of section 3, the following text:Protein retention means ranged from 14%–28% for the nine aquatic species, and 13%–37% for livestock. Calorie retention means ranged from 6%–25% for the aquatic species, and 7%–27% for livestock. Chickens performed best for both protein and calorie retention, followed by Atlantic salmon.Revision:Protein retention means ranged from 14%–28% for the nine aquatic species, and 10%–34% for livestock. Calorie retention means ranged from 6%–25% for the aquatic species, and 5%–25% for livestock. Chickens and Atlantic salmon performed best for protein and calorie retention.
- 3.The last sentence in the second paragraph of section 3:Chicken has the highest mean protein retention (37%), due to a low FCR (1.9), low feed protein level (18%–23%), and high edible portion (0.70–0.78) (table 1).Revision:Chicken has the highest mean protein retention (34%), due to a low FCR (1.9), low feed protein level (18%–23%), and high edible portion (0.63–0.73) (table 1).
- 4.In the third paragraph of section 3, the following sentence:Similar to above, chicken and Atlantic salmon have the highest mean calorie retention: 27 and 25%, respectively. Pigs have an FCR (3.9) that is less efficient than chicken and aquatic species, but high calories in edible flesh (211–304 kcal per 100 g) and the high edible portion (0.68–0.76) improves pig calorie retention (16%).Revision:Chicken and Atlantic salmon have the highest mean calorie retention: both 25%. Pigs have an FCR (3.9) that is less efficient than chicken and aquatic species, but high calories in edible flesh (211–304 kcal per 100 g) improves pig calorie retention (11%).
